Architecture That Supported Modernization of Japan

Home , 1980s in Japan, 1983 in Japan

100th Anniversary of Enactment of City Planning Act and Building Standard Law

008 010 013 019

Architecture027 029 030 031 032 That Supported Modernization of Japan052 055 056 059 060

100067 selected069 071 078 083 088 building technologies An English Summary 096

Edited by: Committee for: “Architecture Published by: The Building Center of Japan That Supported Modernization of Japan” The Japan Architectural Education and Information Center Preface

Preface FUKAO Seiichi Chairperson

2019 marks the 100th year since the enactment of the Urban Building “Structural Methods”, Building Production/Facilities” and “Policy/Re- Law, the predecessor of the Building Standard Law, and of the City gional Planning”. We then asked 91 experts who specialize in these Planning Act. areas to write about the “100 Key Terms” from the viewpoint of a his- The Urban Building Law is considered to be the first established tory of the technological progress of construction, newly developed building legislation in Japan, which proceeded the current Building building spaces that resulted from technological progress, and their Standard Law after several amendments. influences on our lives and on society in general. During this period, we have experienced drastic changes oc- “Architecture that Supported the Modernization of Japan – 100 curred in the political and economic sectors and in society as a whole. selected building technologies” is a book that was compiled as a pub- Accordingly, cities and architectures also changed, which were sup- lication to commemorate the 100th Anniversary of the enactment of ported by the innovation of building technologies. All of these changes the City Planning Act and the Building Standard Law. eventually brought about a remarkable reform in our lifestyles. This English translation of the original Japanese summary of the To shed light on the advancement of building technologies that booklet was made so that people in other countries might appreciate have supported modern and current Japan and provided a basis for the accomplishments mentioned within it. these changes, we asked not only architects, but many experts of var- We will be pleased if the “100 Key Terms” gives you a good over- ious disciplines, such as sociology, economics, history, urban planning all picture of the Japanese architecture and building technologies that and journalism, as well, to identify “100 Key Terms” related to Japa- have been developed over the last 100 years, along with their unique- nese architecture and building technologies. The selected “100 Key ness. We hope that the wisdom and ingenuity of the people who cre- Terms” were classified into five categories: “Housing, “Buildings, ated these things becomes evident to all of the readers.

Members of the committee for “Architecture that Supported Modernization of Japan Members of Working Group – 100 selected building technologies” Chief (Operating WG) Chairperson OMI Yasuo (cited above) Professor, Faculty of Engineering, Department of Architec- FUKAO Seiichi Professor Emeritus, Tokyo Metropolitan University ture, Tokyo City University

Members Chief (Editing WG) ASAMI Yasushi Professor, Graduate School of Engineering, Department of ISO Tatsuo (cited above) Architectural journalist (Executive Officer, Flick Studio Co., Ltd) Urban Engineering, The University of Tokyo ISO Tatsuo Architectural journalist (Executive Officer, Flick Studio Co., Ltd) Members INOUE Shouichi Professor, International Research Center for Japanese Studies OTAKE Ryo Managing Director, The Building & Housing Center of Japan. Inc EBARA Sumiko Associate Professor, Faculty of Engineering, Chiba University OMI Yasuo (cited above) Professor, Faculty of Engineering, Department of Architec- OMI Yasuo Professor, Faculty of Engineering, Department of Architec- ture, Tokyo City University ture, Tokyo City University KUMAGAI Ryohei (cited above) Associate Professor, Faculty of Engineering, Department of KUMAGAI Ryohei Associate Professor, Faculty of Engineering, Department of Architecture, Tokyo University of Science Architecture, Tokyo University of Science GONDO Tomoyuki (cited above) Project Associate Professor, Graduate School of Engineer- GONDO Tomoyuki Project Associate Professor, Graduate School of Engineer- ing, Department of Architecture, The University of Tokyo ing, Department of Architecture, The University of Tokyo HAYAMI Kiyotaka (cited above) Professor, College of Engineering, Department of Architec- SASAKI Hiroshi President, Center for Housing Renovation and Dispute Set- ture, Nihon University tlement Support YAMAMICHI Yuta Flick Studio Co., Ltd HAYAMI Kiyotaka Professor, College of Engineering, Department of Architec- ture, Nihon University Observers MATSUBA Kazukiyo Professor, Musashino Art University Building Guidance Division, Housing Bureau, Ministry of Land, Infrastructure, Transport and MATSUMURA Shuichi Project Professor, Graduate School of Engineering, Depart- Tourism ment of Architecture, The University of Tokyo Urban Building Division, Housing Bureau, Ministry of Land, Infrastructure, Transport and Tourism MIISHO Kiyonori Chairman, Japan Federation of Architect & Building Engi- neers Associations (Professor Emeritus, Shibaura Institute of Technology) Members of a round-table talk for “Architecture that Supported Modernization of Japan YAMANA Yoshiyuki Professor, Faculty of Science and Technology, Department – 100 selected building technologies” of Architecture, Tokyo University of Science YOSHIKAWA Hiroshi Professor, Faculty of Economics, Rissho University UTIDA Yositika Professor Emeritus, The University of Tokyo YOSHIMI Shunya Professor, Graduate School of Interdisciplinary Information OKADA Tsuneo Professor Emeritus, The University of Tokyo. Advisor, The Studies, The University of Tokyo Japan Building Disaster Prevention Association TATEISHI Makoto Former Director of Housing Bureau, Ministry of Construc- tion. Former President, The Building Center of Japan MURAKAMI Shuzo Professor Emeritus, The University of Tokyo. President, Insti- tute for Building Environment and Energy Conservation (IBEC) FUKAO Seiichi (cited above) Professor Emeritus, Tokyo Metropolitan University

(as of end/March 2019)

C2 100 SELECTED BUILDING TECHNOLOGIES Overview

Overview: Modern and Contemporary Japan Supported by Architecture

For this booklet, 100 key technical terms were selected in order to holistically review the progress of Japanese architecture and building technologies over the last 100 years. Each selected technology was developed and introduced to materialize buildings required of the respective time. There have been many cases, on the other hand, when structures built with new technologies had a significant impact on society, which eventually brought about important social changes. We have roughly classified the 100 technologies into four periods over the last 100 years, in order to reflect the historical changes of technologies. This was done with a view to clarifying what society expected from architecture and buildings in each of those periods, and what these building technologies provided for society. Please note that this classification of technologies is not limited to the four periods, as some of the technologies have been in use for a long time.

Part 1 Establishment of Modern Japan and Building 1868–1935 Technologies

Beginning in the modern Japan, Japan proceeded to establish a modern nation, under the slo- gan of “Enrich the Country, Strengthen the Army”, following the development of the U.S. and European nations as models. This also meant to establish cities which were not in the least in- ferior to those in the Western nations. Modernization of urban areas, as seen in the fields other than urban development, began with advanced technologies that were adopted by Japan through the efforts of a number of foreign professionals employed by the Japanese government, and of Japanese students sent to Western countries to study. After the 1900s, Japan gradually modified these imported technologies to make them more suitable for Japanese culture, and situations unique to Japan, and eventually developed its own technologies and applied them to practical applications. In this period, many government buildings and cultural facilities were built using these modern building technologies as symbols of the modernization of urban cities. In accordance with industrial development, business activity increased dramatically, and many financial and commercial systems were developed, which required construction of modern buildings in urban areas as centers of business activities. To respond to the need for such buildings, innovative technologies became indispensable, such as reinforced concrete structures, steel structures, elevators, and technologies related to electric equipment, lighting appliances and so on. Also, an increasing number of people started working for newly established companies in urban areas, who, together with military officers and government officials, formed a new social stratum. For these people, a new style of housing was provided in areas such as residential suburbs, which were equipped with newly developed facilities, such as modern kitchens and flush toilets. The economic growth of the period enriched people’s lives, which led to increased consumption and more opportunities for recreational activities. Commercial and entertainment centers were developed to satisfy people’s needs and new types of buildings, such as a station building with a shopping center, were constructed. Prevention of infectious diseases was one of the most serious issues that was addressed by urban policies in Western nations, and so it was in Japan, which led to the introduction of modern medicine. For buildings, the importance of a good hygienic environment was recognized, which facilitated the improvement of toilets and provided rat-proof measures to prevent the plague. These efforts, along with improved medical services, people’s awareness of sanita- tion and better nutrition, resulted in the successful reduction of the number of deaths due to cholera, dysentery and the plague, which had been prevalent in Japan until the beginning of the 20th century. [Fig. 1]

01 100 SELECTED BUILDING TECHNOLOGIES Overview

180,000 700 The Great Kanto Earthquake occurred in persons persons 1923; the first large disaster to hit Japan after Dysentery Plague modernization. This had a huge effect on Cholera (on the left scale) 160,000 (on the right scale) (on the left scale) building technology. Since the beginning of 600 the modernization, Japan introduced West- ern style building techniques, mainly the 140,000 brick-structure method, which, however, did 500 not secure sufficient strength against large

120,000 earthquakes. Since then, many other structural methods have been adopted, such as a reinforced concrete structure, a steel struc- 400 100,000 ture and a steel-encased reinforced concrete structure, together with seismic design technology. The effectiveness of seismic designs 80,000 300 against earthquakes was proved through the experience of the Great Kanto Earthquake, and in 1924, seismic design provisios were 60,000 incorporated in the Japanese building stan- 200 dards for the first time, which were called the

40,000 Enforcement Regulation of Urban Building Law. This provision can be said to be a signif- 100 icant result of the development of modern 20,000 building technologies that had been accumulated in Japan since its modernization, which was praised as the world’s leading building 0 0 regulation at the time. 1876 1878 1880 1882 1884 1886 1888 1890 1892 1894 1896 1898 1900 1902 1904 1906 1908 1910 1912 1914 1916 1918 1920 1922 1924 1926 1928 1930 1932 1934 1936 1938 1940 1942 After the Great Kanto Earthquake, the Fig. 1—Change in Number of Deaths by Infectious Disease — most seriously damaged building structure Many lives were lost before the middle of 20th century in Japan by infectious disease, which were rampant due to poor health was a post-and-beam wooden structure. The standards and poor hygiene. number of completely collapsed buildings [Source: Infectious Disease Statistics, compiled by the Ministry of Health, Labor and Welfare] was 130,000. From this experience, installation of diagonal braces was found to be effective in enhancing structural strength against earthquakes. This was stipulated in the building standards and is now used in all wooden housing. Historically, urban areas of Japan, where most of the buildings are of wooden structure, have suffered a number of conflagrations. In the Great Kanto Earthquake, as one example, most of the deaths were due to large fires. In view of this fact, lath-mortar construction, which was a fireproof technique for wooden housing, became the prevailing method for the fireproofing of wooden housing. Additionally, “Dojun-kai”, a public housing corporation that was established for the rebuilding of housing after the Great Kanto Earthquake, played a large role in the construction of multi- unit residential buildings, which were well received by the masses.

Part 2 The War - Slumped Period of Building Technology 1935–1955

The prolonged Sino-Japanese War, followed later on by the Pacific War, had a huge influence on building technology in Japan. Supply of all materials was strictly controlled by government, as they were needed to produce military supplies, which severely constrained the development of building technologies. Thus, provision of housing for the labor force became a problem, such as for coal miners. This issue continued after the Wold War II, when a priority production system went into effect. The most critical subjects of research and development in this period were an air defense technology and a system to prevent conflagration in urban areas in order to mitigate the damage caused by the war. This research regretfully did not produce effective results during the war but yielded great results after the war in regard to preventing extensive urban fires. Throughout the country, a number of cities were burned to ashes during the war, which created a housing shortage of 4.2 million units . Moreover, there was a severe shortage of building materials, such as wood, due to an acute demand for rebuilding on the destroyed property, including industrial facilities. This period may be considered to be the most difficult time for building technology in Japan. Under such circumstances, efforts were made to overcome this difficulty by developing building techniques such as designs for minimal houses and alternative building materials including bamboo-reinforced concrete.

02 100 SELECTED BUILDING TECHNOLOGIES Overview

Part 3 Building Technologies Supporting Economic Growth 1955–1990 and Affluent Living

In 1955, when the first stage of restoration activities was almost completed, the Japanese economy recovered to reach the peak level before the World War II, which occurred in the latter half of the 1930s. An economic white paper that was produced in 1956 noted that, “It is not the post-war period anymore”. The Japanese economy entered a full-fledged growth period, which brought about great changes in society. In the building sector, engineers were faced with the challenge of innovation in building technology. Economic growth brought about a vast demand for building construction, which was in- tended to create new concepts of space and of town planning. To satisfy the demand with limited time, labor and material resources, a variety of technologies were developed to rationalize building production and construction processes.

Large Supply of New Style Housing

Immediately after the war, the Japanese population was less than 80 million, but rapidly increased to 90 million, by 1956, and in 1967, it reached 100 million. Accordingly, population concentrations from local areas to large cities had become conspicuous, in line with economic growth. [Fig. 2, 3] Thus, new technologies were required in order to supply housing to those new 14,000 70 urban inhabitants. To address this issue, a new housing policy was formulated that encouraged persons % Percentage of land development for large-scale residential projects and development of building technologies three metropolitan populations 12,000 to the total population 60 for housing under the initiative of the public sector. This was led by the public sector; Japan (on the right scale) Housing Corporation (currently, Urban Renaissance Agency) and Publicly Operated Housing 10,000 50 Corporations in each region. The private sector also was quite active, and the housing industry established new housing-supply systems in the form of condominiums and multi-units housing 8,000 40 Total population for rent, in addition to the conventional detached-housing supply. (on the left scale) 6,000 30 After the World War II, Japan experienced significant conceptual reformation concerning “family”. One was the nuclear-family trend, and the other was the spread of post-war democra- 4,000 20 cy, which emphasized the importance of the individual and one’s independence. Accordingly, in Population in three metropolitan areas the housing sector, new designs were introduced for public housing, based on the idea of “sep- 2,000 Tokyo, Saitama, Chiba, Kanagawa, 10 Aichi, Kyoto, Osaka and Hyogo prefectures aration of the dining room from rooms for sleeping” and “separation of bedrooms for parerents (on the left scale) and for children”. This basic idea has continued to have a great influence on Japanese housing 0 0 to this day. 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Fig. 2–Change in Total Population and Three Metropolitan Populations with Ratio – The Japanese population increased by 2.3 times in 80 years. Economic Growth and Demand for Offices In the three metropolitan areas, it increased by 3.6 times, which made the supply of housing a big social issue. [Source: National Census, compiled by the Ministry of Inter- During the period of rapid economic growth, expansion of tertiary industries was remarkable, nal Affairs and Communications] especially in large cities, where the number of office employees was increasing drastically. Nu- merous office buildings were constructed, which led to the development of skyscrapers.

200 100 In line with the advanced IT technologies that emerged later, a new type of office building, 2 units m referred to as “an intelligent building”, was developed. The latest IT technologies were adopted 180 90 for the building functions. 160 80 Average ﬂoor area (on the right scale) 140 Housing starts 70 (on the left scale)

120 60 Improvement of Living Standard along with Expanded Consumption 100 50

80 40 As income levels rose, the demand for more comfortable and a convenient lifestyle grew, which 60 30 included modern housing facilities, such as Western-style toilets and gas water heaters, as well

40 20 as modern housing that could accommodate such amenities. The prolonged housing shortage abated in 1973, when the total number of existing housing 20 10 units exceeded the number of households, which meant that Japan was at the turning point “from 0 0 quantity to quality” of housing. In that period, people’s requirements for housing became diversi- 1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002 2006 2010 2014 2016 fied, with new needs created in accordance with social change. New systems of housing supply Fig. 3–Change in Housing Starts and Floor Area of Housing Unit and residence types were introduced, such as a “Cooperative House” (building co-operatives). – As incomes increased, so did consumption, which facilitated construction of commercial Housing starts surged from the latter half of the 1960s, and and recreational buildings in various forms, such as shopping malls and theme parks. New the average housing floor area reached 80m2. [Source: Housing Starts Statistics, compiled by the Ministry styles of urban space were created under urban redevelopment projects, which incorporated of Land, Infrastructure, Transport and Tourism] mixed-use buildings of offices and residences, and spacious public areas.

03 100 SELECTED BUILDING TECHNOLOGIES Overview

Furthermore, an innovative technology that allows for large roofs that were unsupported by interior columns was developed and put to practical use, which resulted in construction of large-scale domes, arenas and exposition facilities to be used for large events.

Buildings as Symbols of Hope

Before the World War II, newly constructed modern buildings were regarded as symbols of the progress and prosperity of Japan, as well as the dreams of its people. They were dignified government buildings, magnificent office buildings, splendid department stores and theaters, which formed a spectacular urban scape in the city center. After the war, however, while values of the Japanese society drastically changed to the equality principle in society, open-design modern architecture that eliminated decorative designs became the dominant style for government and office buildings. On the other hand, buildings used for national events, such as Olympic games and World Expositions, were built with the contemporary design that represented the era of each event. At that time, peace memorial facilities and towers were also built as monuments of memories and hopes that are widely shared by people. Japan, which had achieved an unprecedented economic growth rate, also pursued advancement in architectural design. Modern Japanese architecture started with learning about, and then introducing, Western style architecture. After that, it went through a unique development process, and a number of structures have been built that are highly evaluated around the world for their design.

Building Technology Contributing to Economic Growth (Growing Investment for Buildings and Building Technologies)

In line with economic growth, investment in building construction increased sharply. In 1960, the area of building construction starts totaled 66 million square meters, which increased to 267 million square meters in 1973, four times what it was in 1960. Investment in tertiary industries, i.e., commercial and service industries, as well as the housing industry, showed outstanding increases. [Fig. 4] 30,000 As investment in buildings played an important part in the national economy, more effi- m2 cient, faster and safer building construction was required, and thus the development of new technologies was strongly required to rationalize construction processes. At the same time, Others safety measures for construction workers also made considerable progress. As a result of these 25,000 Public service use technical advances, the increase in construction laborers (for both building and civil engineering) was only about 1.5 times during this period, in spite of the remarkable growth of construc-

Tertiary industry use tion projects. Under these circumstances, a shortage of skilled workers became a serious problem, es- 20,000 Commercial use pecially in the housing sector, such as carpenters who had long supported the Japanese wooden-housing industry with their superb techniques for constructing traditional wooden struc- Mining and manufacturing tures. Therefore, more efficient housing supply mechanisms and technologies were required, industry use 15,000 together with the urgent need for a large supply of housing as previously mentioned. This was Agricultural/Forestry /Fishery use achieved by transferring some of the conventional on-site building works to in-factory production processes, where the prefabricated house system and the two-by-four housing system Residential/Industrial mixed use were adopted. This, at the same time, evolved into the establishment of a housing industry that 10,000 became one of the modern Japanese industries, which developed innovative building systems, Exclusive residential use including factories for large-scale housing components. This movement further evolved into a new phase of technological progress. Besides building up a large number of housing, securing the quality of housing became an 5,000 urgent matter. For this issue, the specifications of housing published by the then Government Housing Loan Corporation played a great role. On the other hand, however, a significant number of defective houses were found at that time, which became a serious social problem. To cope with this issue, new housing-policy measures were formulated from the viewpoint of 0 consumer protection, one of which was the Housing Performance Indication System. 1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 Fig. 4–Change in Total Area of Building Starts (classified according to use) – In accordance with economic growth, the investment for Building Technologies to Cope with Frequent Natural Disasters buildings increased rapidly, especially for those of residential use, commercial use and the tertiary industry use. [Source: Building Starts Statistics, compiled by the Ministry While the national economy showed incredible growth, a great number of congested quarters of Land, Infrastructure, Transport and Tourism] of wooden housing that were built before the World War II and in the post-war period still re-

04 100 SELECTED BUILDING TECHNOLOGIES Overview

mained in many cities. Until 1960s, fires often occurred in these areas, creating large urban conflagrations, These disasters gradually decreased as rebuilding of old wooden buildings were undertaken, to which new fireproof technologies were applied. Since the 1970s, the number of large fires has significantly decreased due to the improvement of firefighting capabilities.- How ever, the risk of extensive fires occurring in urban areas still remains, especially in the event of large earthquakes. Thus, the issue of the congested urban areas of wooden buildings still exists as a challenging issue. The “Shirokiya Department Store Fire”, in 1932, was the incentive for the formulation of fire prevention measures for large-scale buildings, and all others that are open to the public. After that, openining fireprotective assembly was greatly improved, based on the experience of many fires and the knowledge gained as a result of them. Remarkable progress was seen in the research of fire safety of modern buildings, which allowed for the construction of new building-design methods that helped prevent the spread of fire, and for evacuation during fires. These technical developments eventually led to the introduction of the performance-based building regulations/standards and further progress in building technology. Japan has been hit by a number of catastrophic earthquakes since the Great Kanto Earth- quake. Every time a large quake occurs, considerable research is done regarding damage to buildings. Based on the improvement of structural techniques, the building standards were revised. Furthermore, great advancements have been made in seismic design technology, and the use of computers for structural design became common. All of this technical progress enabled the construction of skyscrapers and buildings with large spaces without support columns, both of which had previously been “the buildings of dreams”. The result of the progress that the building standard reached became the New Seismic Standard. More recently, innovative technologies such as a seismic isolation system and a response control system were introduced, with the aim of establishing more advanced safety measures. As seismic technology improves, it has become a challenge to secure the safety of existing buildings that were constructed according to the previous standard, which led to the development and diffusion of seismic retrofit building technologies.

Part 4 Growth to Maturity: Building Technology Supporting 1990– the Future

After the period of high economic growth, Japan experienced a bubble economy, followed by its collapse, which caused drastic changes in society and to people’s sense of values. While the rapidly aging population and the global environment have become challenging social issues, the building sector was expected to support the coming society by development of new technologies.

Evolution to Diversified Society and Revitalization of Regional Resources

It has been necessary to create spaces where everybody, including the aged and persons with disabilities, can lead active lives. This requires housing for the elderly and building technologies such as barrier-free and universal designs. Regional characteristics should also be an important factor. During the period of high economic growth, it was encouraged to develop every region in a uniform manner, in order to remain impartial. Recently, however, unique regional characteristics that were formed as a result of the local climate and history have caught on with many people. Accordingly, new building techniques are currently being explored to support, for example, the renovation and reuse of existing cultural resources, such as traditional buildings and streetscapes.

Transformation to Sustainable and Stock-based Society

In the high economic growth period, abundant resources were allotted for the construction of numerous buildings. This, at the same time, entailed demolishing the buildings that they replaced, thus creating a vast amount of waste. As social awareness of the global environment grew, however, the building sector was required to make efforts to realize a sustainable society through technological progress. It was during the oil crisis in 1973 when measures of promoting techniques for proper insulation and building energy saving were implemented as resource conservation measures in the building sector. Since then, building technology has made steady progress, and now, more

05 100 SELECTED BUILDING TECHNOLOGIES Overview advanced innovation is expected, such as development of sustainable buildings. Furthermore, recent research has proved that improvement of the indoor thermal environment greatly contributes to the promotion of people’s health. When looking back on the history of Japan, it is not difficult to imagine that the remarkable advancement of indoor climate of housing that was made in post-war Japan has contributed to the longevity of the Japanese people today. The improved indoor environment is now anticipated to help reduce the cost to the government for national health care. As such, the roles and responsibilities expected of building technology have become further diversified in society. However, the introduction of new building technologies has brought about some health hazards, such as asbestos health damage and the sick-building syndrome, for which proper technical measures were taken for these problems. Annual industrial waste in Japan totals about 400 million tons, of which 80 million tons (20% of the total) is from the construction industry, with one-third of that being related to buildings. As effective use of resources and a reduction of waste have been serious issues in all sectors, including the domestic and industrial areas, it is required to improve technologies for the re-use and recycling of goods. In the building sector as well, technologies for building renovation and conversion are expected to be further improved, in order to continue using the stock of buildings that has accumulated over the years. One of the most notable building materials that is expected to contribute to the creation of a sustainable society is wood. In post-war Japan, the use of wood was highly restricted, due to the devastation of forests, for which restoration has recently been completed. Currently, the use of wood is rather encouraged, as it is a recyclable material. Innovative technologies to compen- sate for the disadvantages of wooden structures have been developed, such as fire-resistivet wooden buildings and large-scale timber buildings. Along with these technologies, new structural evaluation methods have also been formulated, such as structural analysis for traditional wooden buildings, which are expected to further expand the potential of the usage of wood. It is expected to continue the efforts to make further progress in the field of wooden construction. Although a variety of new technologies were introduced for housing construction during the mass-production era, 40% of newly built housing and 70% of total detached houses have been built with the conventional Japanese post-and-beam structure. About half of them were built by local contractors and carpenters as custom-built detached houses. Historically, conventional post-and-beam building techniques have contributed greatly to the remarkable progress of the building sector, as well as to the socio-economic development of Japan. These days, however, a serious problem has emerged in the wooden housing sector, which is the reduction in the number of skilled workers and the rapid aging of those currently in the field.

Contribution to International Society

The various building technologies introduced in this booklet were developed in response to the social needs of each time, which have supported the social progress of the modern/contemporary era of Japan. Some of them were developed in other countries and modified in Japan to suit the situations here, and some were invented in Japan and developed here. Making use of these accumulated building technologies, Japan has continued to dissemi- nate building information overseas to maintain communication with the global society. Japan also has provided technical assistance to a number of developing nations around the world. In the field of seismic engineering, Japan’s cooperation with the US and other nations has generated considerable mutual benefits to all parties. A Japanese technology for earthquake preparedness, which is the world leader of such technology, has made a notable contribution to safety in other countries. Japan has also made great efforts to facilitate the formation of international measures toward the global environment issue by, for example, organizing Sustainable Building 2005 (SB05). These efforts are ongoing, by means of the provision of information and technical assistance to various countries around the world. It is expected that Japan will further contribute to the world community based on experience accumulated in the field of building technology in Japan. As described above, Japanese buildings and building technology have made progress in line with the development of Japanese society over the last 100 years. The progress of building technology has made great contributions to various aspects of society, such as the improvement of housing, which is fundamental to people’s lives, the creation of spaces for various social activities, better safety and security in the event of disasters, the enhancement of the level of culture, along with improving people’s sense of value. Additionally, the rationalization of the building production system has played an important role in the growth of the economy. Still now, efforts are being made to realize a sustainable and mature society. The progress of building technology will continue to support society by responding to the issues and requirements of each era.

06 100 SELECTED BUILDING TECHNOLOGIES I HOUSING Commentary

Post-War Housing Shortage and Standard- Resolution of Housing Shortage and the Chapter ization/Industrialization Following Trend One of the most serious social issues in Japan In 1968, the total number of existing houses ex- after the World War II was a shortage of housing ceeded the number of households in Japan. As units, which totaled about 4.2 million units. In the housing shortage problem was statistically order to provide an enormous number of hous- resolved, the housing issues shifted drastically ing units with limited materials and human re- from standardization and industrialization to sources within a short period, standardization how to address the diverse housing demands of and industrialization of housing production and the people. In the 1970s, some attempts at pro- supply were vigorously promoted. A new hous- viding “open buildings” were made in order to ing policy was established, which was called respond to the needs of residents, which al- “three pillars of the post-war housing policy”, lowed for flexible designs, through the “infill” i.e., the Government Housing Loan Corporation method, by assembling generally distributed (GHLC), Publicly Operated Housing Corpora- housing components. However, in Japan, the tions and Japan Housing Corporation (JHC). The technical aspect of separating interior finishing I latter two mainly supplied multi-unit residential from structural members was so emphasized buildings, namely, publicly operated housing that such housing units were established as and JHC housing [004], for which standardized skeleton-infill house (base building and fit-out

HOUSING designs and housing components were utilized, for housing) [020], which mainly aims to provide as well as industrialized building techniques and long-life housing. Other attempts to explore new materials, such as a pre-cast concrete. Large de- systems of housing supply and new lifestyles velopments of JHC apartment complexes were attracted people’s attention, such as cooperative widely referred to as Danchi [005], and an exten- house (building co-operatives) [009]; whose resi- sive number of new towns [006] were planned dents, in the initial stage, organize a co-opera- and constructed in the suburbs of metropolitan tive that is to be involved in the planning, design areas. Most of the publicly operated and JHC and operation of the building, and collective housings were initially multi-units for rent, how- housing [010], which provides some common ever, beginning in the 1950s, supply of condo- spaces, such as a dining room, so that the resi- miniums [007] began in urban areas, along with dents can share some time together every day. those supplied by the private sector, which is At the same time, the average household that currently the predominant type of housing in Ja- was established in the post-war period, consist- pan. In 1962, the Act of Unit Ownership of Con- ing of a couple with two children, and which had dominiums was enacted, which legally estab- previously been the premise for housing design, lished the rights of unit owners of condominiums. now occupies a lower position, both socially and The other pillar of the post-war housing statistically. Currently, therefore, it is required to policy was the establishment of the GHLC, supply housing to meet the diversified needs of whose function was to provide housing loans, residents, of which one example is housing for mainly for construction of conventional post- the elderly [016]. and-beam wooden houses. It also contributed to As for the materials and building systems, the improvement of housing quality through the while prefabricated housing starts remained at a GHLC Specification [014], which was used as the level of a little more than 10% of the total num- technical criteria required to qualify for housing ber of newly built detached houses in around loans. The industrialization of detached houses 1980, the majority of existing houses were built was first attempted shortly after the end of the by the conventional wooden post-and-beam Industrial Development and Population war, when some architects designed prefabri- method, thus the quality and rationalization of Concentration in Urban Areas cated housing [018], which had consequently led conventional wooden houses emerged as an im- to the construction of minimal houses [013], with portant issue of the housing policy. Under such After the Meiji Restoration, Japan achieved a re- an aim to pursue modern living spaces, in spite circumstances, a pre-cut technique [021] devel- markable level of industrial modernization of the limited availability of resources. In this pe- oped in the 1970s gradually spread throughout through the First Sino-Japanese War and then riod, many non-housing related industries, such the wooden housing industry. It encouraged ra- the Russo-Japanese War, which brought about as munitions manufacturers, entered the housing tionalization techniques for conventional post- dramatic growth of urban populations. For those industry with the intention of a peaceful output of and-beam houses, such as factory-fabrication of who migrated to urban areas, apartments first their industries. In the 1960s, the prototypes of structural members. With regard to multi-unit became available as high-end, multi-unit resi- large prefabricated housing manufacturers ap- residential buildings, construction of skyscraper dential buildings in the early 20th century. In the peared in the industry, which thrives today. The condominiums [011] started around 1990, which new industrial cities and the surroundings of government also facilitated the industrialization was technically supported by the development large factories in rural areas, high-density apart- of housing production by utilizing the GHLC loan of high-strength concrete. Their construction ment complexes were constructed for the work- system, which was further promoted in the 1970s was accelerated by the trend of people returning ers, which was best represented by coal miners’ by some pilot projects [019], such as a design to city centers, as well as amendment of the reg- housing [003]. Around the same time, renovations competition for the Ashiyahama High-rise Resi- ulation to allow the construction. Regardless of of slums and substandard houses were under- dential Project and other pilot housing projects. detached or multi-unit housing, people’s aware- taken in urban areas as a government measure On the other hand, the concentration of ness of housing quality has continued to be to improve deteriorated urban environments. populations in urban areas that occurred in the heightened, due to successive earthquake di- During this period, railway companies devel- era of high economic growth brought about un- sasters, the problem of defective housing, the oil oped residential areas outside of inner cities, planned residential developments, as previously crisis, and the energy saving consciousness that which are called residential suburbs [001], mod- seen before the war, which eventually led to the followed. In response to the demand of the peo- eled after developments in Western countries. congested districts of small wooden multi-unit ple, the Housing Performance Indication Sys- After the Great Kanto Earthquake, an associa- housing operated by private sector [008] in the tem [017] was put enacted in the year 2000. After tion named “Dojun-kai” was established as a peripheries of urban areas, that were called experiencing recent natural disasters, including national restoration program. They constructed “wooden rent-house belt zones”. There was an the Great East Japan Earthquake, it is urgently Dojun-kai apartments [002], which were designed overall trend towards housing standardization, required to review production system of emer- with ingenious layout plans, and were equipped which however did not conform to the conven- gency temporary-housing and restoration with modern facilities and common spaces. The tional existing local houses, in regard to the re- housing [012] to allow for flexibility, in order to suit Dojun-kai was also engaged in housing supply, spective regional characteristics. One of the typ- the actual situation of each affected area, such with the objective of improving the quality of ical examples of such local-based housing was as aging and declining population. housing in Japan. cold-region housing [015], which was developed in Hokkaido prefecture.

07 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS I HOUSING 1—Housing Supply System

1 Adoption of Howard’s “Garden City” idea and the Japanization of it

—Housing Supply System 001 The “garden city” concept proposed by Ebenezer Howard 120 years ago was introduced to Japan at the end of the Meiji era. It has been materialized as residential suburbs ever since the 10’s of the Taisho era. The business model of the Japanized “garden city” was to develop residential suburbs in conjunction with railroad construction, in order to generate revenue from train fares in addition to that from the housing project, which would be Residential Suburbs used to cover the enormous initial investment of the residential developments. By providing new styles of daily life facilities and adding new functions to the area, such as inviting educational institutions to locate there, these residential suburbs were then developed under the names of “healthy city”, “cultural city” and “college city”. In some of these suburbs, the landowners jointly implemented extensive land-adjustment projects, which still exist as high-end residential suburbs.

A multi-dwelling building complex as a town, created as part of earthquake recovery effort 002 Dojun-kai, an incorporated foundation established by the Japanese government for the reconstruction of houses that were destroyed by the Great Kanto Earthquake, built multi-dwelling buildings of reinforced-concrete (RC) structures in various places in Tokyo, which were called Dojun-kai apartments. Dojun-kai apartments were designed to harmonize with the surrounding environment, and thus create scenic Dojun-kai street landscapes so that they would be favorably accepted by the masses. Apartments Dojun-kai provided various types of units to accommodate multiple types of households including single-family dwellings and were provided with community spaces for the residents. Around the Dojun-kai apartments, facilities, such as restaurants, public bathhouses, barber shops, clinics, and houses with small shops, were provided to support the residents, which would allow for the area to function as a town.

Housing complexes built by companies as a part of production plan 003 Housing for coal miners was constructed in direct connection with coal production. It was a part of the necessary facilities for coal production from the viewpoint of the employers. Along with housing, various other living facilities were provided in large-scale collieries, which made them nearly self-sufficient towns like colonies. During the World War II, these collieries were actively constructed as one of the national programs, which then Coal Miners’ contributed to the economic recovery after the war. Shortly after, however, their economic role ended with the Housing revolutionary change of energy resources. It may be said that coal miners’ housing was a sort of flow-type housing, which continually wavered as the fortunes of the coal mining industry fluctuated.

A standard design, which contributed to the modernization of lifestyles 004 Publicly operated housing and JHC housing contributed to the rationalization and modernization of people’s lives through the development of a standard housing-design. This design also served as a showcase for housing development in the private sector. As a result of a survey of people’s lifestyles, the basic requirements for housing units were identified as “separation of the dining room from rooms for sleeping” and “separate bedrooms Publicly Operated for parents and children”. Based on these people’s wishes, a standard design for publicly operated housing, Housing and Japan called the “51C Type”, was established in 1951. This became a prototype of a floor plan called a “2DK” (two rooms combined with a dining room & kitchen). Depending on the floor plan, a notational system, which includ- Housing Corporation ed “nK” and “nDK”, was used for housing supplied by JHC that was established in 1955. As the standard hous- (JHC) Housing ing design became widespread, standardization of housing design came to be seen as restriction in the 1970s. Since then, flexible housing-systems have been developed to meet the diversified needs of people.

The fruit of architectural planning study that supported the living standard of post-war period 005 After the World War II, one of the serious issues in the building sector was the provision of housing. There were numerous families who urgently needed housing, due to the destruction from the war as well as the post-war baby-boom. To cope with this issue, the Japan Housing Corporation (JHC) was established in 1955, which then constructed a number of Danchi. (“Danchi” is a large-scale housing complex consisting of multi-unit residential Danchi buildings, which were mainly supplied by the public sector in Japan.) For the purposes of fire-resistant housing construction, hygiene and the diffusion of a modern urban lifestyle,danchi were initially built of RC structures, with a floor plan that provided a dining room and bedrooms separately. These units were equipped with a stainless-steel sink and a western-style toilet. This was done in an attempt to create a desirable housing style in the future through the cooperation of industry, academia and government agencies.

002 003 005 007 100 Key Terms

08 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS I HOUSING 1—Housing Supply System 001

Integrally planned and constructed large-scale residential cities 006 In post-war Japan, housing construction and urban development were urgently required to cope with the loss

of housing during the war and also to deal with the rapid expansion of urban areas occurred afterwards. 010 To address these issues, large-scale, planned residential developments were carried out, which were called New Town developments. New Towns After the development of Senri New Town, the first of this type of development which was begun in 1960, a number of New Towns were constructed throughout the country, following the Senri model of development. These included self-sufficient emerging urban areas surrounding existing large cities, and also new develop- II ments located in rural areas, which were developed aiming at promotion of regional industries.

From housing for high income people to that for the masses after booms 007 Condominiums are supplied and managed under an institution concerning ownership of multi-unit residential buildings. They appeared in Japan in the 1950s and were increasingly constructed after the Act of Unit Owner- ship of Condominiums went into effect in 1962. There were several booms of condominium construction: the first one in 1963 and 1964, the second one in 1968 and 1969, and the third one in 1972 and 1973. Through these III Condominiums construction booms, condominiums were eventually established as a typical residential building in urban areas. Condominiums in Japan have played an important role in the diffusion and the improvement of mid-high-rise multi-unit residential buildings of RC structure.

Wooden rental housing to accommodate a rapid migration to urban areas IV 008 Just after the war, the rental housing market was sluggish due to the war damage and also the continuing government control of rent. In the 1960s, the private sector became active in the supply of rental housing. In the same period, population migration from rural to urban areas increased, which pushed up the demand for rental housing in large cities. It was wooden, multi-unit rental housing that satisfied the acute demand. Multi-Unit Housing There were quite a few wooden multi-units rental housing in unfavorable conditions, which had shared toilets, Operated by Private shared kitchens and shared entrances. These housing units were phased out after their peak construction period in 1968. Sector At that time, the structures of multi-unit rental housing were gradually changed from wooden to non-wooden. However, the average floor area of each unit remained at the same level, about 40m2.

A system to avoid the stereotyped housing design of multi-unit residential buildings V 009 Cooperative house is a multi-unit housing system by which a union of residents purchases a plot, places orders for a building design and construction, and then arranges for maintenance and management activities to be carried out after occupancy. This type of housing was introduced to Japan in the 1970s, mainly in metropolitan Cooperative House areas. The advantages to the residents of a cooperative house are that they can purchase the land and the build-

ing at the actual price, eliminating an agent fee, and individuals can design their own units. Shortly after the 100 (Building co-opera- introduction of cooperative house, residents themselves usually undertook the hiring of a contractor. This, however, has gradually changed; nowadays it is common for a private coordinator to find people to buy into cooper- tives) ative house projects. Large-scale cooperative house, called “co-op-towns”, have been developed by the public sector, such as local housing-supply corporations.

A new style of co-living proposed for swaying family model 010 Collective housing is a multi-unit building whose residents cooperate on some of their daily life activities in a shared space, while still having some privacy. This type of housing emphasizes the importance of dining together, and thus has a common dining room and kitchen, in addition to individual ones in each housing unit, which is one of the key characteristics of the spatial Collective Housing design of collective housing. The pioneer project of collective housing in Japan was one that was supplied as disaster-recovery public housing for the Hanshin-Awaji Great Earthquake. In 2003, the most advanced collective-housing project to date, called Kankan Mori, was opened by the private sector, where residents are sharing the housework, childcare and so forth.

008 010

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 001 – 010 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

09 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS I HOUSING 2—Living Standard

Technical development that realized construction of tower condominiums 011 Until the early 1970s, multi-unit housing that were built on the outskirts of cities, such as danchi, were all mid- rise buildings of around five stories. The era of high-rise condominiums, such as skyscraper condominiums, began in 1974, which was marked by the construction of an 18-story RC condominium called the Shiina-machi Apartment. Skyscraper Since the late 1980s, construction of skyscraper condominiums was further accelerated and in the 2000s, the Condominiums scenery of skyscraper condominiums became a familiar part of the urban landscape. The construction of these skyscrapers was enabled by an accumulation of technical development in various fields, including structural technologies, construction site works, and designs for buildings and interior of housing units.

From post-war public housing construction to an extensive support for housing 012 Construction of emergency temporary housing and restoration housing by the public sector have been the core of housing support for people affected by disasters, which was in line with the post-war government housing policy. Through the experiences of the 1994 Hanshin-Awaji Great Earthquake and the following several large disasters, new, extensive housing development measures have been created, in addition to the conventional procedure of Emergency Temporary constructing individual buildings. These include a linkage with various other land development projects, an Housing and adoption of various systems for ordering construction works and building materials, and a re-use of the existing housing stock. Restoration Housing These attempts may lead to the new housing support system for the future, which will be established based on the mature housing market mechanism and be designed to best suit each regional circumstance.

2 Aiming at equal rights for habitancy

—Living Standard 013 After the World War I, the possibility of providing “minimal houses” was studied in Europe as a measure to accommodate the vast number of immigrants who flowed into urban areas. Most of those European minimal houses were multi-unit residential buildings, but those developed in Japan were detached houses. Minimal Houses To the question “How much affluent living can you provide with a limited floor area and budget?”, many architects answered in various ways with their own design capabilities. However, in the period of high-economic growth, the significance of “minimal houses” was diversified in accordance with changes of social circumstances.

A design and construction manual that enhanced housing quality in post-war Japan 014 In 1950, the Government Housing Loan Corporation (GHLC) was established for the purpose of solving the severe shortage of housing. In order to provide housing with sufficient quality, the GHLC set technical criteria, which were slightly higher than the level of the Building Standard Law and required the housing to meet those criteria as a condition for approving loans for them. This program was implemented in conjunction with the GHLC Specification building permit system. The GHLC Specification is a manual that describes materials and building methods to be used in order to satisfy criteria so that home builders and craftsmen may properly proceed with building construction. After a number of amendments, the GHLC Specification still plays an important role in improving the quality of Japanese wooden housing.

Technical development of housing that is suitable for cold regions with heavy snowfall 015 Historically, Japanese houses were built for summer weather. Thus, they were not suitable for cold climates with heavy snowfall, especially that of Hokkaido. After the World War II, therefore, “cold region housing” was developed for the specific purpose of improving the lives of the people of Hokkaido. Cold-region housing is the fruits of the cooperative efforts in research and development made by a number of Cold-Region Housing engineers, researchers and administrators in Hokkaido. These R&D efforts continued after the development of the cold-region housing, which led to the development of the current energy-efficient housing and Housing for Northern Areas. Cold-region housing provided a basis of residences in areas of cold weather with heavy snowfall.

013 019 100 Key Terms

10 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS I HOUSING 3—Rationalization of Production I

Housing proposed to address the extreme population-aging in Japan 016 The housing for the elderly that is described in this section refers to a small room of a barrier free design for a

single resident or a couple. 011 These units are, in most cases, in multi-unit buildings, which provide services such as monitoring, emergency treatment, daily life consultation, meals and nursing care. Housing for the It was in the latter half of the 1980s when the Japanese government began to take measures to provide ade- Elderly quate housing for the elderly, with the implementation of the Silver Housing Project.

Other government programs for senior housing include nursing homes for the elderly, established under the Act 021 on Social Welfare for the Elderly in 1963, and housing for the elderly with home-care services, which was started in 2011.

A system for properly evaluating housing technologies 017 The Housing Performance Indication System is a method of rating the level of performance of a housing unit, based on standardized criteria, which then indicates the evaluation results. This system helps homebuyers to compare the quality of housing and also to settle housing-related disputes when such cases occur after the purchasing. Housing suppliers also find the method to be beneficial in receiving III Housing Performance orders, based on their technical superiority. Indication System With this system, fair assessments have been made on technologies developed by the housing industry, which contributed to the betterment of the housing market. Now, this system is indispensable for providing communication between homebuyers and housing suppliers in addition to creating a quality stock of housing.

3 Houses produced and supplied in a similar way that automobiles are IV

—Rationalization of Production 018 Beginning in the 1960s, the Japanese housing market grew dramatically, which encouraged other industries to enter this attractive market, such as those of iron, steel, chemical, and electric appliances. These industries were seeking more productive manufacturing and supply systems for housing through industrialization, instead of continuing with the conventional wooden-house building system that relied on traditional carpentry methods. Prefabricated They had an eye on light-gauge steel material, which had just been put into practical use at that time, and de- Housing veloped housing structural systems utilizing this material. In the same period, other housing manufacturers entered this market who used concrete for the structural material and wooden components for the same. All of these new housing systems, called “prefabricated houses”, were flexibly changed and created new styles of houses to meet consumer demands, which were gradually accepted into the Japanese housing market.

Linked with changing issues of housing administration of each period V 019 Nowadays, the word “pilot” is commonly used to mean “a person who operates an aircraft”, but it originally meant “a guide in waters, or a specialist who assists a captain of a ship in guiding it over rough seas”. In the field of architecture, “a pilot project” means a building project carried out as a test of some unestablished tech- Pilot Projects nology to determine whether it is worthwhile to further develop it for a practical application.

In the housing sector, especially, a number of notable pilot projects have been conducted over the years to ad- 100 dress issues of government housing-administration.

Durable housing with diverse functions and flexibility 020 For planning of multi-unit residential buildings, a method to separate structural members (the frame/skeleton) from the interior/equipment (infill) has been employed to meet the diversified needs of residents and to allow flexibility for changes in residents’ member and lifestyles. As a result of many technical developments and the related regulation changes, multi-unit skeleton-infill housing (base buildings and fit-out for housing) has gained Skelton-Infill House popularity, as it ensures that residents can continue living in the unit for a longtime. (Base building and As the environment and natural resources issues have become increasingly serious, the use of durable frames/ fit-out for housing) skeletons and flexible infill systems are the ideal responses to the current social requirements.

A technique of processing wood that supported Japanese housing construction 021 The majority of newly built detached houses in Japan are built with conventional post and beam construction. Traditionally, those wooden members were made by carpenters using hand tools, but nowadays they are made with machinery. Previously, machines were only used for simple processes which has recently become capable of more compli- Precutting cated processes and their abilities are continuously being improved. Thanks to the wide use of precutting techniques, the time and cost required for building houses have drastically been reduced, and the on-site work has become safer and more efficient. Precutting is an indispensable building technique, which has supported the Japanese culture of wooden detached houses. It is a building technique unique to Japan, which was developed based on the Japanese building module.

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 011 – 021 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

11 100 SELECTED BUILDING TECHNOLOGIES II BUILDINGS Commentary

Public Buildings was introduced to provide public open spac- Chapter es [035] with an integral design program. Many From the late Meiji period through the Taisho pedestrian decks [034] were constructed to pro- era, Japan became a modernized nation, which vide safe and comfortable walking spaces by was brought about in part by the construction of allowing people to avoid automobile traffic inter- various public facilities. Major styles of public sections. buildings that are currently existing already appeared in that period, including government Urban Renewal buildings, schools, train stations, hospitals, city halls, museums and so forth. Since 1980s, urban redevelopment [036] project As for school buildings [022], the use of a schemes have been undertaken in major cities in government standard-designs formulated at the Japan, integrating offices, commercial build- end of the Meiji era gradually expanded after the ings, hotels and cultural and multi-dwelling war, quickly addressing the growing demand for functions into one building complex by greatly construction of schools. After 1970, however, increasing the floor-area ratio. Many new urban some very ambitious schools started to adopt centers have been created through this type of II new building designs for their buildings. Before projects. Urban waterfront development [037] the World War II, public cultural facilities [023], projects were implemented in many cities to re- such as museums, art galleries, theaters and new deserted port areas, which previously had

BUILDINGS concert halls, were built in large major cities, warehouses and factories, into lively places, which were, in the post-war period, constructed which attracted people from outside the area. in each prefecture, and then after 1990, many of The shopping mall [038], a new type of large- these were built in cities, towns and villages scale commercial facility, became popular as an around Japan. A standard design for govern- alternative to department stores and traditional ment buildings [024] was established before the shopping centers. war, which was applied to the majority of prefec- tural government buildings. After the war, a Lively Spaces number of city/town office buildings were built in a modern architectural design. These were Historically, buildings have created vitality in ur- considered to be symbols of municipalities, not ban areas. Immediately after the World War II, it simply as offices for local administrators. was black market districts that firstly recovered the vigor in burnt-out cities. Later on, these ar- Architecture as a Symbol eas were further developed and transformed to the currently existing downtowns [039]. Later on, A building is expected to serve as a symbol, be- in accordance with people’s growing desire for sides having practical functions. Religious leisure time, various theme parks [041] were de- buildings and memorials [027] are typical exam- veloped, where people can experience special ples, which are built with the most effective entertainment in an extensive facility, designed function as symbol. A tower [028] is constructed to express a specific theme. Manyconvention for broadcasting purpose and is familiar to peo- centers [040] were also built as a new type of ur- ple as an icon of a city, and also as a monument ban facility, where people came from far away that marks time, as people recall when it was for various purposes, e.g., commercial activities, constructed. At international events, such as the exhibitions, cultural exchanges, tourism, etc., 1964 Tokyo Olympics [029] and the Japan World which contributed to forming new lively spaces. Exposition, Osaka [030] in 1970, buildings and facilities designed by notable architects of the time appealed to the world as profiles of what Japan was, and what it strived to be. It can be said that modern architecture [025], which totally eliminated decorative features from buildings, was at one time an attempt to reject the idea of buildings serving as symbols, which, however, eventually became a symbolic style of architecture that represented the modern era. Post-modern architecture, which arose from criticism of modern architecture, was trying to incorporate regional features into buildings. Okinawan architecture [026] is typical of buildings that represent this movement in Japan.

Urban Environment

Urban populations have increased dramatically over the last 100 years. Various new problems have occurred due to sudden urban growth. New technical proposals were made to solve these problems. One proposition to create safe and comfortable shopping spaces for people gathering in city core areas was the arcade [032], which is a pedestrian street with a roof, and the underground mall [033], with the intention of transferring an entire aboveground-shopping town underground. Another example is the station building with shopping centers [031], combining facilities for shopping as well as for transportation, which is a type of commercial building developed solely in Japan. In order to secure open spaces in congested urban areas, a new plan

12 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS II BUILDINGS 1—Public Buildings / 2—Architecture as a Symbol I

1 Rising above a uniform design building to become characteristic regional centers

—Public Buildings 022 Construction of school buildings in modern times began in line with the inauguration of a new educational institution in the Meiji era, which was greatly revised after the World War II, and has been further modified from time to time in accordance with the social environment of the time. For the one-hundred years from the beginning of Meiji era, efforts were made to standardize school-building design in order to urgently meet a demand for con- School Buildings structing a number of school buildings. During the fifty years after early 1970s, it has been explored to find the ways how school buildings may comply with a diversified educational system, may contribute to the fulfillment of people’s lives, and may cooperate with each regional community. Currently, school systems are expected to meet the demands of issues related to the IT society, combined elementary-junior high school systems, the global en- 022 vironment, promotion of the use of wood in the construction of their buildings and a safe and secure environment.

Japanese school administrations are also required to cope with the current problems of the deterioration of old 026 buildings and a declining birthrate, together with the aging population. To address these issues, it is expected that school buildings be suited for multiple functions, including that of being the center of the regional community.

From a place for appreciating others’ performances to a space for expressing your creativity 023 Part of the modernization of Japan included the modernization of cultural facilities, which brought about the con- III struction of public theaters/halls and museums/art museums. Theater/hall buildings initially served as public halls for meetings and assemblies, and then their use was expanded to include various other purposes, such as music performances and plays. Then, there appeared new facilities that are specialized in certain types of performances, Public Cultural and, on the other hand, multi-function facilities and their accompanying technologies were also developed. In the Facilities area of art museums, exhibition rooms called “white cubes”, which were made in order to appreciate modern art- work, have been gradually changed to the places where people may have various spatial experiences that are created by the contemporary art. Public cultural facilities as well have been changed, from being places where people appreciate others’ artworks and performances to spaces for people to create things and to express themselves. IV

From symbolic design to post-war modernism 024 Construction of government buildings in the Meiji era started with the adoption of Western designs and building technologies, and with symmetrical floor plans and façades that emphasized symbolic characteristics. At the end of the Taisho era, most government buildings had a box-type external appearance, similar to office buildings, and were equipped with a tower that exhibited a strong symbolic feature. After the World War II, the idea Government of democracy influenced government building construction. Traditional designs that might recall feudalism were Buildings totally renounced, and instead, clear and bright modern designs were sought as an ideal style for government buildings. At the end of the 1950s, a government building-construction boom occurred as a result of the enactment of the Law for Promoting Consolidation of Municipalities, when fifty government buildings were newly constructed nationwide within three years. V

2 Modernism in Japan coinciding with the European movement

—Architecture as a Symbol 025 Modern architecture is characterized by the utilization of industrial materials, which were generated by the in-

dustrial revolution, for the structure and design of buildings, rejecting conventional architecture. 100 During the 1920s in Japan, “the secession school of architecture” was founded as a pioneer of modern architecture. During this period, the disciples of F. L. Wright grew out of their mentor’s style, trying to pursue modernism. Modern Architecture This movement in Japan coincided with the growth of modern architecture in Europe. In the 1930s, Japanese architects who studied in Europe came back to Japan and established the era of modern architecture in Japan.

One of the practices of post-modernism 026 The Nago city office, completed in 1981, turned out to be a monumental building, deeply rooted in the history and climate of the region. For the exterior, concrete blocks were utilized, which were commonly used in Okinawa under the occupation by the U.S. It was equipped with statues of “Shisa”, an Okinawan talisman that wards against evil; and had a terrace on each floor to provide shade. Okinawan Since then, a number of buildings have been built with strong references to Okinawa, its climate and its history. Architecture Okinawan architecture and its steady and persistent improvement have attracted the attention of the world as one of the greatest achievements of post-modern architecture in Japan.

022 024 025 026

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 022 – 026 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

13 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS II BUILDINGS 3—Urban Environment

A merger of modernism and symbolism 027 Religious buildings and memorials that represent spirituality had long played the leading part in Japanese architecture. Since the modern era of architecture, the importance of architecture associated with spirituality has diminished, but the substance of these buildings still remains in the consciousness of architects. Religious Buildings For example, Tange Kenzo successfully achieved a high-level of integration of modernism and symbolism in his and Memorials designs of a Christian cathedral and a war memorial museum. New religions that emerged in Japan after the World War II constructed a number of huge-scale buildings that adopted advanced structural technologies to enable free and innovative building designs.

Repeatedly been destroyed by monsters in movies and advertisements 028 During the 1950s, many shared broadcast-transmission towers were constructed in major cities in Japan, including Tokyo, Osaka, Nagano and Sapporo. For each tower, an observation platform was provided on one of the upper floors, where many people visited and enjoyed the views. Tower Tokyo Tower, which was once the most famous of all the Japanese towers, was said to be a symbol of post-war restoration and the high economic growth that followed in Japan, which gave hope to Japanese people for a prosperous future. It was repeatedly featured in movies and advertisements in Japan.

Showcasing post-war restoration with the fruits of engineering knowledge 029 In 1964, The Olympic Games were held in Tokyo, which was the first time they were held in Asia. New transportation systems were developed for the Olympic Game, they were: the Tokaido Shinkansen railway and the Tokyo Metropolitan Expressway together with the Inner Circular Route. Also, Olympic stadiums and many other facilities were constructed, such as Yoyogi Gymnasium and Komazawa The Tokyo Olympics Olympic Park, whose excellent architectural designs were highly evaluated throughout the world. It was a great opportunity to showcase, both within and outside of the country, Japan’s post-war restoration and the globalization of Tokyo, which were realized by achievements in national land-planning, city planning and planning of buildings.

An opportunity to experiment with new building-technologies 030 In 1970, a world exposition was held for the first time in Asia, in Senri Hill, Suita city in Osaka prefecture. At the site, the organizer and a number of the participating nations and companies exhibited eye-catching facilities and pavilions and competed for the best building design and uniqueness. Furthermore, many innovative technologies for structures and site works were introduced, such as space-frame- Japan World and lift-up construction methods, a capsule structure, a membrane structure and an air-beam structure, all of Exposition, Osaka which had considerable impact on the further progress of building technologies in Japan. 1970

3 Super intensively used urban building complexes unique around the world

—Urban Environment 031 Hankyu-Umeda station built in 1920 was the first Japanese-style station building that had a department store as a tenant. Since then this type of station buildings spread throughout Japan. In the post-war recovery period, the National Railway Corporation constructed many station buildings that comprised commercial functions with public-private joint financing, which were called “people’s railroad stations”. After the breakup and the privat- Station Buildings with ization of the National Railway Corporation, the new railway companies actively took up development of such Shopping Centers station buildings, which produced huge projects such as the Kyoto Station Building and Osaka Station City. The Japanese station building, best represented by Shibuya station, is a multi-use urban building complex that provides networks connecting the station and the surrounding facilities. It is still changing to make a type of building that is rarely seen in the world.

027 029 030 031 100 Key Terms

14 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS II BUILDINGS 4—Urban Renewal I

A buffer space created by a collaboration of shops along the street 032 The word “arcade” originally meant a corridor or gallery covered with a series of arches. Nowadays, arcades serve as avenues and shopping streets that are covered by roofs. The origin of the Japanese-style arcade goes back to the sunshade used in the Edo and Meiji eras. The current style of arcade appeared in the early 1950s, and was constructed until early in the Heisei era, during which the Arcade design changed every ten to twenty years, influenced by the fashion of the respective period. Now they are often found in large cities and in regional urban centers. An arcade, with the colored walkways and the streetlights, is a commonly shared facility which works as an II important element for creating the urban image. It can be said that an arcade is a unique space that connects private properties with public areas. 027

A distinctive Japanese-style development in densely populated urban areas Underground malls typify overpopulated cities in Japan. They are all-weather pedestrian spaces that connect 033 036 railway stations and the surrounding buildings, which are still making progress distinctive of Japan. It was before the World War II when the first Japanese underground mall was constructed, as what was called “a Subway Store”. These were then constructed throughout the country during the period of rapid economic growth. III Underground Mall Their construction was halted when a large fire, the Osaka Sen-nichi Department Store Fire, occurred in 1972, but the construction resumed in the late 1980s. There are now many large-scale underground shopping malls in Japan. There is no other country in the world that has developed so many underground malls of such enormous scale.

From a pedestrians-vehicle separation system to three-dimensional-space use in urban areas IV 034 In the 1960s, an increasing number of accidents involving pedestrians became a serious social problem, which brought about the provision of pedestrian lanes above existing roads to separate pedestrians from automobile traffic. In Kashiwa city, such pedestrian lanes were merged into an urban renewal project, the Kashiwa Station East Project, which was completed in 1973. In this project, an entrance of the elevated station building, and the Pedestrian Decks surrounding buildings were linked by an artificial ground, which was the first pedestrian deck in Japan to provide an overhead walking network for people. Since then, this procedure has been adopted for many large-scale urban renewal projects nationwide. It is an effective urban-infrastructure system that is unique to Japan.

A measure to integrate urban environment contribution and building code deregulation V 035 Public open space is a public space provided on a building site in various forms, such as a sidewalk, a through passage, an atrium, a waterside open space, a square open space, etc. When a building owner agrees to provide a public open space that contributes to the improvement of an urban Public Open Spaces environment, some concessions are made by the government to the developer, in proportion to the level of the

contribution. These can be in the form of relaxation of the regulations for floor-area ratio, building height limit, 100 and others. This system is stipulated in the provision for “specific blocks” in the City Planning Act, and in the Building Standard Law for a “integral design system”. Since the 1970s, it has become common to provide public open spaces in skyscraper construction and large- scale redevelopment projects.

4 Creating an urban core for revitalization of cities

—Urban Renewal 036 In 1969, the Urban Renewal Act was enacted, with a view to facilitating the efficient use of urban land and improving functions of cities. Initially, this act was mainly applied to projects of consolidating small, dispersed building lots in order to create urban cores for modernized commercial activities, as well as to improve disaster prevention capability. After the Urban Redevelopment late 1980s, there was a social trend towards deregulation and inducement of private-sectors to be involved in public works, which facilitated the execution of huge redevelopment projects, such as those on the sites of demolished factories, water treatment plants and former freight stations, turning them into multi-function building complexes that comprised offices, hotels, commercial facilities, cultural facilities and housing.

032 034 036

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 027 – 036 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

15 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS II BUILDINGS 5—Lively Spaces I

Taking attractive environment around harbors back to urban areas 037 Urban waterfront development: The renovation of port areas previously occupied by warehouses and factories into charming shopping streets and parks where people can enjoy themselves. This urban development method, which reminds us of the beauty of waterfront area, came into fashion in Japan 10 years later than that when it occurred in the US. It began in Japan with the opening of Kushiro Fisherman’s Urban Waterfront Wharf in 1989, which was followed by various developments in major port cities, such as Tokyo, Yokohama, Development Nagoya, Osaka, Kobe and Fukuoka. In the 21st century, constructions of skyscraper condominiums and offices on waterfront property have been II booming, which made the area draw people’s attention again.

Safe and comfortable commercial districts developed in suburbs In the late 1990s, many shopping malls designed by an American architect, Jon Jerde, were built one after an- 038 037 other in Japan. The technique of creating safe and comfortable shopping spaces, combined with pleasant pathways, was a completely new approach from the one for conventional shopping centers which had spread across Japan, ac- 041 Shopping Mall celerated by the trend of mass consumption in the period of high economic growth. Since then, Japanese developers have rapidly caught up and have constructed a number of shopping malls in the suburbs. However, it is now a challenging time for them, considering the continuously decreasing population.

5 Lively commercial and entertainment centers IV

—Lively Spaces 039 In the early-modern times, there were places of amusement for people to gather, which were located in the peripheries of cities. In the modern age, those amusement functions were drawn into the center of cities, which were further developed and formed downtown areas. In these areas, streets were lined with shops of various exterior designs, Downtown which were pleasing to passersby. During the period before and after the World War II, the government attempted to develop planned downtowns, such as the Shinsekai district in Osaka and Kabuki-cho in Tokyo. Immediately after the war, there emerged many black markets around railway stations, which gradually grew and eventually formed downtowns.

Multi-function facilities that accommodate various groups of people V 040 There are several types of assembly halls; those for conferences organized by international organizations and ac- ademic institutions, for product exhibitions held by enterprises, for sports and entertainment events, and so forth. It used to be that a different type of building was constructed for each type of event, e.g., those for conference Convention Center hall, exhibition hall, sports arena, etc. However, at the beginning of the 1980s, new types of convention facilities

were constructed, which integrated multiple functions into one facility in order to correspond to the needs that 100 arose from the increasing scale and diversification of events. As convention centers are efficient tools to attract numerous people from an extensive area, they are expected to play an important role to vitalize the city who competes with other cities.

The world separated from daily life 041 Theme Park: a different sphere, apart from daily life, created based on a specific theme, such as an exotic atmo- sphere, or the history of some country or region. The name “theme park” originated in 1983 in Japan, when Tokyo Disneyland opened. Looking back at history, there were similar facilities opened during the 1960s in Japan, such as Nara Dreamland Theme Parks and Meiji Village Museum. Going further back to seek the origin of theme parks, it was found that some entertainment facilities and those for simulated pilgrimage (visiting one large temple where model buildings of many other temples are constructed in the precinct, so that the visitor may have simulated experience of visiting all the temples) in the Edo era were operated in a similar way to present-day theme parks.

037 040

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 037 – 041 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

16 100 SELECTED BUILDING TECHNOLOGIES III STRUCTURAL METHODS Commentary

Introduction of Modern Structures and Development of Higher/Larger Buildings Chapter Japanization While the basic styles of the Japanese building Historically, wood was the only material used for structure were established, and, on the other building structures in Japan. However, since the hand, ongoing overseas building information was modernization of Japan, a variety of structural continuously flowing into Japan, the possibility materials and methods have been introduced, for constructing much larger-scale buildings had beginning with brick construction, which been raised. This technology made remarkable evolved the current building technologies. Then, progress during the post-war growth period, with the first adopted as a modern building material the representative example being the Kasumigas- was a steel structure [043] which was first used in eki Building, completed in 1968. This was Japan’s the latter half of the 19th century but to a limited first skyscraper [050] realized through a thorough extent, and then its use gradually increased in utilization of prefabrication techniques that were accordance with the introduction of American applied to pursue a safe and efficient construc- construction methods. Soon after that, in the tion process. This consequently promoted indus- early 20th century, a reinforced concrete struc- trialization of construction projects in Japan. In III ture [045] was introduced, which was valued as accordance with the growing social needs for an effective seismic structure suitable for Japan, large-span buildings, such as exposition and a quake-prone country. Therefore, a great sports facilities, together with the progress of

METHODS STRUCTURAL amount of theoretical and practical researches structural technologies and new materials, new was made on this structure. As there were many structural methods were developed, which in- concrete-form carpenters, cast-in place was cludes the tubular structure [051], the shell-and- commonly practiced for concrete works in Ja- spatial structure [052] and the membrane struc- pan. However, while searching for easier, more ture [053]. Later, a retractable-roof dome [054] was economical and efficient construction proce- built that is suitable for seasonal changes, which dures, a concrete block structure [042] also came is now in common use as sports facilities. into use, mainly for housing construction. The latest invention that was made following these Evolution of Wooden Structures structural developments is a steel encased reinforced concrete structure [044]. This was a Since the era of the modernization of Japan, a va- unique seismic structural method, which be- riety of structural types have been adopted. At the came an indispensable technology for construc- same time, considerable technological progress tion of high-rise buildings in Japan. was made to the original Japanese wooden building. Steady advances were made to seismic Establishment of Seismic Design and technology for wooden housing [055], based on Technology accumulated research data obtained as a result of a number of earthquakes. This accelerated the The structural technologies introduced from over- spread of the application of braces and bearing seas have gradually been improved their seismic walls. Also, wooden fire-preventive construc- performances in response to the requirements tion [058] came into wide use, which was facilitated of this earthquake country. A seismic design by the extensive conflagrations that destroyed provisions [046] were established before the wooden buildings during World War II. A mor- World War II, which is to secure required seis- tar-coated external wall, one of the approved fire- mic strength by length of bearing walls. These proof specifications in Japan, was a typical build- design provisions were developed based on the ing element that characterized Japanese post-war concept of seismic intensity proposed by Toshi- houses. The two-by-four building [057] system was kata Sano. After the war, the seismic standard introduced to Japan, mainly from North America, was drastically advanced through a number of as a new structural method, which was quite dif- earthquake disaster experiences, which was fol- ferent from the Japanese conventional wooden lowed by amendments to the seismic legisla- structure. This structural method was standard- tion. Finally, the New Seismic Design Provisions ized and incorporated into the Japanese building were created in 1981, which has formed the standards in 1974, which became available with- basis of the current seismic design. Further- out any special approval. The system was mainly more, a seismic isolation system [047] was intro- used for detached houses, and gradually became duced, which is an innovative system to sepa- recognized in Japan due to the simple construc- rate buildings from seismic forces; a completely tion process that is involved and its strong seismic different system from the anti-seismic structure, properties, which is realized through the large which allows buildings to resist seismic forces quantity of bearing walls used in this system. through their rigidity. As another technology to After the war, on the other hand, non-wood- reduce seismic vibration transmitted to build- en buildings were dominant in urban areas, ex- ings, a response-control [048] technology was cept for small structures such as houses, in order developed, which has increasingly been used for to ensure fire safety in modern cities. From the a number of buildings. It is especially effective beginning of the Heisei era, however, various ad- as a countermeasure for long-period earthquake vanced research efforts and the following dereg- motion of skyscrapers. These new technologies ulations made it possible to construct large-scale are applied not only to newly constructed build- timber buildings [060] and fire-resistive wooden ings, but also for the preservation of traditional/ buildings [059], which were being erected more cultural buildings and the continued use of exist- and more. Since enactment of the revised Build- ing buildings as well. They are called seismic ing Standard Law in 2000, various attempts have retrofit [049] building technologies including seis- been made to enable construction of large-scale mic isolation retrofit, which allows for the preser- fire-resistive wooden buildings. Among the huge vation of a building’s design features yet provid- technical and institutional progress made to- ing protection against seismic activity. Various wards the establishment of new wooden build- other designs and technologies are currently ings, a study of the structural analysis of tradi- being developed for seismic retrofit to corre- tional wooden buildings [056] has made notable spond to the need of the individual building. progress, which now is a world-leading technology, being utilized for the renovation and restoration of buildings of cultural importance.

17 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS III STRUCTURAL METHODS 1—Structural Method / 2—Seismic Technology

1 Structure that supported post-war recovery housing through their fire resistance, seismic —Structural Method 042 stability and affordability In line with Japan’s modernization, “fire resistance” and “seismic resistance” have been ongoing issues for building construction and urban development in Japan. Concrete Block After the war, there was an urgent need to construct buildings as fast as possible, and at a low cost. The concrete block structure was widely used to satisfy this housing demand for a certain period after the war Structures because of its simple construction method that was similar to that of a brick (masonry) structure, applicability of seismic technology already developed for brick structure, fire resistance property and the reasonable construction cost.

Steel structure prevailed due to improved connection techniques and the use of shaped steel 043 A steel structure in Japan was first used at the end of the 19th century, and its use spread rapidly through the period of high economic growth in the 1960s. During this period, tremendous progress was made regarding the assembly method, from conventional riveted joint assembly to the use of H-section steel and high-strength bolted friction-joints, as well as in welding tech- Steel Structures niques. With this structure, a wide range of buildings were constructed, from low- and middle-rise buildings to skyscrapers which was best represented by the Kasumigaseki building. After that, the use of square-steel pipe became common, which was followed by CFT (concrete-filled steel tube).

A unique technology, developed in earthquake-prone Japan 044 A steel encased reinforced concrete structure was developed in Japan by combining a steel structure with a reinforced concrete structure. The Marunouchi building, which was built at the end of the Taisho era, was constructed with a steel structure and then reinforced after the Great Kanto Earthquake. This was done by covering the existing steel columns with reinforced concrete to make each of them an integrated structural member. The Steel Encased head office of the Industrial Bank of Japan was built with a steel encased reinforced concrete structure. Half a Reinforced Concrete year after its completion, the Great Kanto Earthquake occurred, however, it did not suffer any damage as a result of the quake, which drew much attention of engineers. The design method of the steel encased reinforced con- Structures crete structure was fully established in the 1950s and has been used for high-rise buildings of around twenty stories, and for the lower floors of skyscrapers.

Structure that allows for the design of various building forms 045 Due to its excellent seismic- and fire-resistive properties, together with the reasonable construction cost, the reinforced concrete structure has been widely used by architects and engineers in modern Japan. Using this structure, buildings with innovative structural methods were constructed before the World War II, such as domes and other large-span roofs with vaults. Reinforced Concrete In principle, it is possible to form any shape of building with reinforced concrete. This has inspired the creative- Structures ness of many architects, resulting in various attempts to create novel building forms. The fair-faced concrete finish, which has nothing applied to it after the forms are stripped, has been preferred and adopted by many architects for their masterpieces.

2 Changed by earthquake disaster experiences and technological developments

—Seismic Technology 046 The seismic design provisions are structural standards that were established to prevent buildings from collaps- ing as a result of earthquakes. Different from ordinary structural designs, this design does not exclude the possibility of buildings being damaged in quakes. In 1923, the Great Kanto Earthquake hit, and in the following year, the Urban Building Law was revised to incor- Seismic Design porate seismic design provisions, which was the first such building legislation in Japan. Provisions In the 1960s, construction of skyscrapers began in Japan, for which dynamic seismic-response analysis was adopted by utilizing advanced computer technologies. In 1968, the Tokachi-Oki Earthquake caused serious damage to many middle-rise reinforced concrete buildings, which lead to the formulation of the New Seismic Design Provisions enacted in 1981.

積層ゴム支承すべり支承転がり支承

フランジ

積層ゴム

すべり材球体リテイナ

042 044 045 鋼材ダンパー047 鉛ダンパーオイルダンパー source: The Japan Society of Seismic Isolation 100 Key Terms

18 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS III STRUCTURAL METHODS 3—Large-scale Buildings I

The Great Hanshin-Awaji Earthquake verified the effectiveness 047 A seismic isolation system is a system that significantly reduces the amount of damage to buildings as a result of earthquakes. The system equipment is installed between the foundation and the building, allowing it to ab- sorb earthquake energy. It was 1983 when the first seismic isolation system with laminated rubber bearing, which is still in widespread use at present, was applied to a two-story residential unit with a reinforced concrete Seismic Isolation structure. After that, the system was applied on an experimental basis to, for example, facilities of construction Systems companies who were interested in this technology. Its effectiveness was finally verified by the experience of the Great Hanshin-Awaji Earthquake, and since then, the use of the seismic isolation system has been widespread, II being applied to all types of buildings. Currently, the system is used mainly for high-rise residential buildings, large hospitals and the like. Just recently, its application to detached houses has been increasing.

A combination of an elastic frame and quake-energy absorbing walls and braces 048 Even if a building does not collapse as the result of an earthquake, if its columns and beams have undergone plastic deformation, the building can no longer be occupied and will eventually be demolished. Response control was an attempt to prevent plastic deformation of structural members by installing deformable walls and beams. 042 Response Control To realize this idea, many technologies have been developed, such as a steel-plate shear wall, a viscous dump- ing wall, a buckling restrained brace, an oil damper and a damper that uses non-oil viscous material. Another system of this kind is a tuned-mass damper response control device, installed at the top of a skyscraper, which is effective in securing stability of the building and allowing continuous occupancy, even in strong winds. 051

Prevalent since the Great Hanshin-Awaji Earthquake IV 049 As a quake-prone country, Japan has developed seismic retrofit technologies in parallel with the accumulated experience resulting from earthquake disasters. In the Great Hanshin-Awaji Earthquake in 1995, buildings constructed according to the old seismic standard, which was effective until 1981, were significantly affected. Seismic Retrofit From this experience, the Act for the Promotion of Seismic Retrofit of Buildings was formulated to facilitate the implementation of seismic retrofit, which led to the retrofit of many schools and other buildings throughout the nation. There are two procedures of seismic retrofit: one is a conventional method by which the strength and toughness of the building itself are enhanced; the other is to install a seismic isolation system or a response control system to existing buildings.

3 The world’s first super-high-rise building constructed in earthquake-prone area V

—Large-scale Buildings 050 In 1963, the Building Standard Law was revised to abandon the 31-meter building-height restriction. After that, high- rise buildings of 60 to70 meters in height were constructed one after another, such as the Hotel New Otani building. However, the first skyscraper in Japan which exceeded 100 meters in height was the Kasumigaseki Building, Skyscrapers which was completed in 1968. This was also the first skyscraper in the world to be constructed in an earth-

quake-prone area as well as in a region frequently hit by typhoons. 100 To realize the construction of this building, various technical developments were made in many fields including city planning, structural design, facilities, materials and site work. Based on these developments and other technical innovations that followed, the record for the height of a Jap- anese building has been broken every several years since then.

Structural method that forms towers and other space structures 051 Steel-tube is suitable as an axial tension member, as it is light in weight and has high resistance to buckling. When its production technology was established, it was applied to large-scale towers and buildings with long spans. In the beginning, branch joints were used to connect steel-tubes by welding. In the 1970s, a system truss using spherical nodes was developed, which has been widely used since then for roofs of gymnasiums, stadiums, Tubular Structures shopping malls, exhibition halls and airport facilities. Since the late 1990s, steel-tube welded trusses have again been favored by designers for application to airport- and convention-facilities, which realized affluent structural designs utilizing various curved shapes.

049

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 042 – 051 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

19 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS III STRUCTURAL METHODS 4—Wooden Structure

Technical challenge of human beings for centuries 052 From the ancient Roman era, it had been a dream of human beings, as well as a technological challenge for generations, to create a large astylar space where people could gather and meet. The most important technical subject to achieve this end was how to reduce the weight of the structure in order to realize a reasonable, and at the same time, esthetically pleasing structure, which enabled to create light, Shell/Spatial transparent and fluid space. Structures This basic concept is reflected in a “spatial structure”, which is represented by “shell structure” that utilizes form resistance. When overviewing the period from post-war, when shell/spatial structure appeared in Japan, through today, episodes which marked each time in the history come into our minds.

Realization of huge-space buildings, allowing for the use of natural daylight 053 In response to the increasing needs for large-space buildings, membrane was adopted as a lightweight material used for tensile structures, which then became the membrane structure. From the late economic growth period through to the economic bubble time, membrane structure made a remarkable development and a number of characteristic membrane-structure buildings were constructed in Japan. Membrane Structures For the Osaka Expo held in 1970, an air-supported membrane structure, which uses air as a structural material, was introduced in the US pavilion and the Fuji-group pavilion as temporary buildings. Since then, many membrane-structure buildings have been constructed throughout the country, mainly for sports facilities, which can provide huge bright spaces utilizing natural light.

Competing ideas for roof open/close technologies 054 In accordance with the commercialization of sporting events which requires accommodation of large audiences, such as baseball and American football, construction of large-scale sports facilities with retractable roofing was begun. Japan’s first retractable-roof sports facility was the Ariake Colosseum constructed in 1991, followed by the Fu- kuoka Dome which opened in 1993. Retractable-Roof There are several types of mechanical systems to retract roofs, namely, the rigid-panel type, the frame-mecha- Domes nism type and the membrane folding-type, with each type having its own different variations. Unlike ordinary building structures, those with retractable roofs require many moving parts, which create various technical challenges that must be solved in the design stage, such as techniques for waterproofing and restrictions on the amount of allowable deformation of structural members.

4 Seismic properties of conventional P&B houses improved through many earthquake experiences

—Wooden Structure 055 The basic idea of the current seismic design for conventional wooden housing in Japan, namely, the wooden post and beam structure, is to resist earthquake forces by using load bearing walls installed with diagonal bracing. In order for the braces to work effectively, it is essential to connect the column head/bottom and edges of the braces firmly with the appropriate hardware. To secure sufficient level of seismic stability of a building as a Seismic Technology whole, it is necessary to provide a required length of bearing walls that are to be placed in good balance for Wooden Housing throughout the building. These seismic design techniques were established over time, owing to the accumulated knowledge from earthquake experiences from the Meiji era. As a result, an increasing number of wooden houses are now seismic resistant.

Extract elements of seismic property and change them into engineering model 056 It is extremely difficult to determine the seismic performance of traditional wooden buildings from an engineering perspective, as they were developed over time by the accumulated experience of carpenters and craftsmen. In order to conduct structural analysis on them, it was necessary to firstly study the mechanism of resisting earthquake forces; secondly, to quantify the aseismic property; and finally, to replace them with an engineering Structural Analysis of model for each type of building structure. Traditional Wooden In the 1980s, it became possible to calculate the seismic property elements of structures, such as rotational resistance of joints, column rocking resistance and effects of isolated column with spandrel walls. Buildings It also became possible to conduct collapse analysis, using 3-dimensional frame models, for which validity can be confirmed by comparison with vibration-test data.

052 055 056 059 100 Key Terms

20 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS III STRUCTURAL METHODS 4—Wooden Structure I

Construction method served as an effective social service system 057 For housing construction, there are various wooden-frame structural methods that have been developed overseas, whereas in Japan, a unique post and beam method has been used for many years. However, after 1974, when the two-by-four structure was stipulated in a technical standard for wood frame construction in the Building Standard Law, this structural method became widespread throughout Japan. Two-by-Four The two-by-four structural method was introduced to Japan not simply as a technique and a building product, Buildings but also as an effective system for providing social services that was common in North American countries. Nowadays, more than 100,000 two-by-four houses have constantly been constructed in Japan. II

A basic factor that characterizes the view of low-rise built-up urban areas 058 The idea of fire preventive construction was initiated before the World War II as a measure to prevent buildings from catching fire as a result of air-raids, by using either lath-mortar, plaster, mud, etc. as external wall coverings. Still after the war, this technique was succeeded and was incorporated in the Building Standard Law as a measure to prevent fire from spreading in urban areas, which had dense concentrations of wooden buildings. Thus, III Fire Preventive external walls finished with mortar and non-combustible siding materials were commonly seen in cities, which Construction became an important element that characterizes townscapes of low-rise urban areas. Fire preventive construction was developed in Japan as performance-based criteria, by which the safety of buildings was verified by conducting tests. Japan was the first country to take this approach, which later became a model for fire research in the world. 052

Expanded the potential of wooden buildings 060 059 After the World War II, construction of wooden buildings was interrupted due to a stringent fire regulation im- posed under the government policy of developing cities of non-combustible construction. Being subjected to external pressure, the regulation was gradually relaxed in the late 1980s, beginning with approval of three-story and multi-unit wooden housing construction. In this century, an increasing number of MLIT (Ministry of Land, Fire-Resistive Infrastructure, Transport and Tourism) approvals have been issued for wooden fire-resistive construction permits Wooden Buildings since the enforcement of the revised Building Standard Law (BSL) in the year 2000. Furthermore, a standard specification of walls for fire-resistive construction was provided in BSL Notification 2014, and in Notification 2018, those of other principle building parts for the same were provided, which includes floors, roofs and stairs. As a result, construction of wooden fire-resistive buildings has become realized, which will further expand the potential of wooden buildings. V Creating novel structures/spaces using traditional building materials 060 From ancient times, wooden structures had been a conventional building method in Japan, which was changed and utilized in various forms to fit the needs of each era. Throughout the history, the possibility of constructing large-scale timber buildings has been explored for various reasons, notably due to a shortage of building mate-

rials during and after the World War II, and later during the economic growth period, with the aim of developing 100 Large-Scale Timber innovative technologies and the consequent expansion of economic zones. Recently, large-scale timber build- Buildings ings have been expected to play an important role in the promotion of the use of wood, aiming at better forest management, the circular economy and fixation of carbon dioxide. The possibility of creating new architectural designs by using large wooden buildings has also been explored. Nowadays in Japan, it is not unusual to find large buildings of wooden structures. To realize these building designs, it was essential to develop large-dimen- sion/high-strength engineered lumber and metal joints, to formulate design standards related to fire safety, and to develop advanced structural-analysis technology.

060

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 052 – 060 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

21 100 SELECTED BUILDING TECHNOLOGIES IV BUILDING PRODUCTION / FACILITIES Commentary

RC Structures and Production Technology of high economic growth, remarkable progress Chapter was made in the design of Japanese housing. Historically, the wooden structure was the sole First, concerning hygiene conditions; vault toilet, construction method in Japan. In the beginning which used to be a common type of toilet, was of Meiji era, Western-style building structures gradually replaced with a flush toilet. However, the were introduced to Japan. First introduced was sewage system was not designed for flush toilets, brick structure and brick buildings were deliber- thus Johkasou systems (domestic wastewater ately constructed with an aim to develop a fire- treatment facilities) [081] was commonly installed, proof city, but they suffered serious damage in which secured the minimum level of required hy- earthquakes. Thus, at the end of the Meiji era, giene. At the same time, the Japanese-type toilet the reinforced concrete structure was intro- (squat type) began to be replaced by the West- duced as an alternative fire-resistive building ern-style toilet [080], which had recently been structure. The first full-scale reinforced concrete equipped with a warm-water rear-wash function. building built in Japan was the Yokohama Thus, the lavatory has been changed from an “un- branch office of Mitsui& Co. Ltd., which was clean room” to a “comfortable room”. covered with exterior tiles [069] as cladding, Innovative changes have also been made IV which was the first such application in Japan, to the kitchen as well, through the introduction and asphalt roofing waterproof [075] was utilized of the dining-kitchen room, which considerably for its flat roof, which had also just been intro- reduced the housework assumed by women.

FACILITIES BUILDING PRODUCTION / duced to Japan. As the reinforced concrete struc- This new kitchen was technically enabled by the ture came into common use, foundation- and introduction of the stainless-steel sinks [078], ground-improvement [065] technologies were also which is mass produced by integral press-mold- introduced, such as the concrete pile. ing, which later led to the development of the Cast-in place concrete [061] was, and still is, built-in kitchen unit. Back in the day, the houses a common method of concrete work in Japan. of common people in urban areas did not have After the World War II, production capacity of bathtubs, thus the people ordinarily used public concrete was remarkably enhanced, due to new bath facilities. This changed with the introduc- production facilities, such as Japanese designed tion of the gas water heaters [076] and the pre- concrete batch-plants and concrete pumps, fabricated bathroom unit [079]. An FRP (fiber-re- which supported the construction boom that inforced plastic) unit bathtub, which was occurred during the period of high economic combined with a washing space, is widely used, growth. On the other hand, pre-cast concrete due to the high waterproof quality of fiberglass products were developed to replace the and its workability. It was initially made for ho- time-consuming on-site formwork. These prod- tels and multi-unit housing, but it later became ucts were reinforced block, which was devel- common for use in detached houses. This was oped from the Taisho era to the beginning of the supported by the development of small, but Showa era, and a precast (PCa) concrete [064] high-performance water heaters. It should be that was manufactured after the war. To respond noted that the ventilation fan [077] greatly con- to the massive demand for housing construction tributed to the innovations of the commode, the in the thriving economy, especially in the public kitchen and the bathroom. sector, PCa was adopted to the standard specifi- Regarding detached houses, new structur- cations of JHC and publicly operated housing, al types appeared after the war, in addition to which unfortunately led to stereotypical design the conventional post-and-beam structure, i.e., houses that looked nearly identical. Also, a the prefabricated structure and the two-by-four pre-stressed concrete (PC) [064], especially PCa structure. For all of these structural methods, var- crimping structure pre-stressed by post-tension- ious new building materials [074] were increasing, came into wide use in the 1970s for build- ingly being used as substrate materials, such as ings of large spans, such as warehouses, stadi- plywood [074], gypsum board, PVC sheet, and so ums and bowling alleys. forth. In recent years, however, the use of these ALC [073], a type of foam concrete, was devel- new materials has made it difficult to disassem- oped in Japan as a lightweight and effective fire-re- ble and sort out materials for re-use and recy- sistive material for small- mid-size steel structures cling from those to be discarded, which is cur- and is now widely used for exterior cladding of rently posing a question regarding their use skyscraper condominiums and also for fire-resis- from the viewpoint of the re-use and recycling tive partition walls in all types of steel structures. of building materials [066]. Instead of steel-reinforced concrete, bamboo-reinforced concrete [062] was used as an Technologies that Support Building Con- alternative material [062] during the war, due to a struction shortage of iron. Still today, research is being done to develop a new type of concrete, which In the early stages of building construction, a steel would be reinforced with an alternative material window-sash was commonly installed, which to steel, such as carbon fiber, in order to prevent was replaced by an aluminum sashes [070] after the reinforcement from rusting due to neutral- the war, and at the same time, factory-made ization and salinity. sashes became popular. Use of these sashes ex- For the exterior finish of concrete structures, tended to the housing sector, which eventually tile, stone, brick and mortar were commonly used made an important contribution to the demand before the World War II. After the introduction of for insulation/energy efficiency [087] that was an exposed concrete-finish [063] to the world by raised as a result of the oil crisis. With the aboli- Antonin Raymond, his Japanese disciple, Kunio tion of the building height restriction in the build- Maekawa used the same concrete finish for his ing standards, increasing number of high-rise building designs after the war, which was in turn buildings and skyscrapers began to appear, used by Tadao Ando, who has designed many which brought about a boom in the installation of world-renowned exposed-concrete buildings. curtain walls [071] as non-load-bearing cladding. Accordingly, the progress that was made for glass Modernization of Housing Equipment/ used for openings was outstanding, and in the Materials 1990s, glass buildings [072], employing a high-performance heat-reflective glass and a Low-E glass, From the post-war restoration through the period took the architectural world by storm.

22 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 1—Production I The progress of electric equipment/light- wooden buildings having been improved, the con- Production Technologies in Future ing appliances [082] has made an enormous con- cern regarding large fires shifted from the spread tribution to large-scale office/commercial build- of fire in urban areas to fires in large-scale build- In the last 100 years, tremendous progress has ings, as well as to other types of buildings. In the ings. To prevent such building fires, legal require- been made in building production technologies. 1980s, as the use of computers became very ments for opening protective assembly [083] Currently, addressing global warming is an is- common, intelligent buildings [086] emerged, in- were strengthened, which led to the improve- sue, along with the aging population and a de- stalled with LAN and other information circuits, ment and diffusion of fire doors/shutters. clining birth rate. As a countermeasure to global which are now standard specifications for large Workers who historically supported all of the warming, every building constructed from now office buildings. building construction had been suffering in awful will be required to be, to a greater or lesser ex- Elevator [084] technology, which is now indis- working conditions and in a premodern labor envi- tent, a sustainable building [088]. Also, under the II pensable for every tall building, was introduced ronment. The labor environment improved chronic labor shortage and demands for work- from the US, and later, when skyscrapers became though, due to the measures to ensure safety of place reform, it is imperative that production ef- common, a high-speed elevator was developed in workers [067], which was implemented by GHQ ficiency in the construction sector be improved Japan, which is now a renowned Japanese tech- (General Headquarters). The Industrial Safety and further. The key issue for improved production is nology. Since 1970, the district heating/cooling Health Act was created in the 1970s, to which a automation technology, such as construction system [085] has commonly been employed for number of amendments have since been made. robots, for which wide use of BIM [068] (an ad- skyscrapers and other office buildings. As a result, the number of fatal accidents involving vanced technology of CAD [068]) is indispensable. While buildings became larger and larger, construction workers has decreased to one-sev- and with the non-combustible properties of enth of the number of a half a century ago. III

1 Dramatically advanced by concrete batch plants and pressure pumps in the economic 061

—Production 061 growth period 063 Reinforced concrete structures of cast-in-place concrete were introduced at the end of the Meiji era. This method was dramatically improved after the World War II, through the introduction of concrete batch-plants and the Cast-in-Place advancement of concrete pressure-pumps and chemical admixtures. In recent years, high-strength concrete of more than 100N/mm2 compressive strength has become widespread Concrete and is currently used for construction of skyscrapers. Various other technical developments have been made, such as a self-compacting concrete, which does not require a vibration compaction process. This evolution has contributed to the creation of architectural masterpieces based on the free ideas of architects.

Materials that symbolize hardship in wartime V 062 In the period from the Sino-Japanese War through the Pacific War, all Japanese industries and laborers were under the control of the government, and in the building sector as well, the use of steel, a major building material, was greatly restricted. Alternative Materials, As an alternative to steel, building-product manufacturers turned to wood, cement, pottery, synthetic resin and

bamboo to manufacture various building products, such as hinges, sash rollers, structural plywood, etc. 100 e.g. Bamboo-Reinforced Much research was done on bamboo regarding its replacement for steel as reinforcement of concrete structures. Concrete It was said that bamboo-reinforced concrete was used for construction of bridges, bunkers and some buildings, which, however, is not known whether it is true or not.

A concrete finish developed in Japan that led the way 063 The world’s first building of exposed concrete is said to be Église Notre-Dame du Raincy (The Church of Notre Dame du Raincy), completed in 1922, which was designed by Auguste Perret. Several years later in Japan, Antonin Raymond designed many buildings of exposed concrete, and became recognized as a world-leading expert in this field. Exposed Concrete After the World War II, Tange Kenzo and some other Japanese architects adopted the exposed concrete finish Finish for the restorations of many public buildings. Inspired by this trend in Japan, many American architects began using this finish. In this way, the Japanese exposed-concrete finish had considerable influence on architecture around the world.

061 062

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 061 – 063 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

23 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 1—Production

Structural method that rationalized construction process leading to realization of large-span 064 buildings The precast (PCa) concrete method is a construction method by which pre-manufactured concrete members are taken to the building site and to be assembled there. PCa Concrete/PC Through this method, mid-rise multi-unit residential buildings were mass produced by using large factory-made, concrete panels. Factory-made columns and beams also came into widespread use, especially for high-rise buildings. The pre-stressed concrete (PC) method is a construction method that applies stress to concrete by using high- strength steel. As it is a method to simplify the construction process of large-span buildings, the PC method has been used for the construction of gymnasiums, stadiums, distribution warehouses, factories and so forth.

An “unsung hero” that has supported buildings for centuries 065 Wooden piles are traditional foundation components, and a part of the technique is seen in the pile dwellings in Switzerland that were constructed before 3000 BC to provide protection from floods. Up until the 1950s, wooden piles were major components to support buildings from underground. In Japan as well, pine piles were found in perfect condition when the Old Marunouchi Building was demolished, which Foundation/Ground dumbfounded many building engineers. Improvement Since the beginning of the Meiji era, concrete-pile techniques were introduced from France and the U.S. in accordance with the diffusion of reinforced concrete structures in Japan. Concrete piles actually supported buildings in Japan from deep underground as a sort of “an unsung hero”.

Resource utilization technology to realize a recycling society 066 Technologies to enable the efficient re-use and recycling of limited resources are indispensable for creating a recycling society. In the building sector, the reuse of materials is the process of removing some of the building components from dismantled buildings and use them for other buildings without any processing. In recycling process, on the Reuse/Recycling of other hand, materials such as concrete and wood collected at dismantling sites are transported to intermediate Building Materials treatment facilities for recycling. For recycling of building materials, technologies are required for three processes: collection and transport of materials, intermediate treatment to render the materials usable again, and the manufacturing of the final products.

To prevent fall accidents at construction sites 067 Until the late 1990s, more than 1,000 workers were killed annually in construction accidents in Japan, which accounted for 40% of the total number of labor accidental deaths. The most frequent types of accidents in this industry are the result of workers falling from buildings under construction. To prevent such accidents, enforcement orders and guidelines concerning scaffolds and safety belts Measures to Ensure were enacted. Safety of Workers Regarding scaffolds, a prefabricated type was developed and has been widely used in Japan, which is to assem- ble a building constructing scaffolding using ladder frame and cross brace. As for safety belts, a conventional body-belt type was used for many years, however, a harness type has become obligatory in order to secure a higher level of safety of construction workers.

Drawing system was fundamentally changed in accordance with progress of computers 068 In the late 1970s, drawings made by CAD, instead of traditional manual drawings, gained popularity among designers, but there also was a strong objection to this trend. However, in accordance with progress made in computer technology, the use of CAD drawings became so dominant that it was almost like a prerequisite condition for the design and building construction works. The CAD/BIM method of drawing was overturned with the changes of a concept of “layer” and “content library”. In the late 1980s, 3-dimensional CAD was introduced, but its use was stagnated due to the collapse of the bubble economy. In the first decade of this century, however, it was reintroduced in a different form, called BIM, and is now about to once again drastically change the system of architectural drawing.

064 066 067 069 100 Key Terms

24 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 2—Materials and Construction Methods I

2 A typical exterior finish that was developed in Japan

—Materials and Construction Methods 069 Buildings with exterior tiles are very popular and commonly seen in Japan. They give Japanese people an image of a modern design and the Western style, even though it is not common in Western countries to tile an entire exterior wall of a building. Exterior tiles were introduced to Japan along with the modernization of the country. These were favorably ac- Exterior Tiles cepted by Japanese people, developed through an ingenious idea and became widespread in Japan, later spreading to other Asian countries. Peeling has been the crucial problem regarding the use of exterior tiles since they were introduced. Overcoming II such difficulty, buildings with exterior tiles are still popular and being constructed today.

A component that drastically improved the performance of building openings 070 Currently, aluminum is an indispensable material as a component of building openings. Before aluminum was introduced by the building industry, steel sashes were used extensively, however, it was quite natural to shift to aluminum, considering its high performances of manufacturing, processing and durability. When aluminum was initially used to manufacture sashes, they were made by simply switching the material III Aluminum Sashes from steel to aluminum using the same production system. It was after the development of the closed section aluminum profiles that aluminum sash became dominant and the age of the aluminum sash industry began. As the demand for high quality housing increased, the performance of sashes was also improved, and various types of high-quality, durable aluminum sashes were manufactured, which are now indispensable components for openings of every type of building.

External wall system developed concurrently with skyscrapers IV 071 “Curtain wall” is normally used as a general term of “non-load bearing wall”, however in Japan, it refers to 064 systematized exterior walls, often installed in skyscrapers. After the war, they were adopted for ordinary office buildings. When construction of skyscrapers began, their use gradually increased, as technologies were developed to secure high seismic strength and durability of vari- Curtain Walls ous finishing materials. Metal curtain walls are prevalent in other countries because of its light weight, but in Japan, the majority of 073 curtain walls are of precast concrete with an outer surface of tile or stone. Recently, new types of composite curtain wall are often used, which are made by combining metal and precast concrete curtain walls.

Transparent buildings realized by technique making supporting members inconspicuous V 072 In the 1920s, Ludwig Mies van der Rohe proposed a plan for a building whose entire exterior would be covered with glass, which was, unfortunately, too difficult to be realized. In Japan, the introduction of a float-glass manufacturing technique in the 1960s enabled the mass production Glass Buildings of transparent-flat glass.

In order for the support members of glass to be less conspicuous, several techniques, such as the SSG (struc- 100 tural silicone glazing) method, the glass rib method and the DPG (dot point glazing) method, were developed in the late 1960s, which paved the way for the design of transparent-glass buildings. Combined with eco-friendly technologies such as double-skin glass, a variety of attractive glass-buildings are being constructed.

High strength concrete light enough to float on water 073 Prefabricated building components were indispensable for the modernization and industrialization of the building production system during the period of high economic growth in Japan. ALC (autoclaved lightweight aerated concrete) was developed in Scandinavia, one of the coldest areas in the world with a long wintertime, as concrete with a high thermal-insulation property. After being introduced to ALC Japan, it was developed to satisfy the specific needs of each era in Japan. ALC is a mass-produced lightweight precast component that has incredible properties, which have contributed to the improvement of fire safety in urban areas, as well as the overall habitability of residences.

071

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 064 – 073 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

25 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 3—Equipment and Environment

Products in widespread use, due to their excellent performance, workability and cost effectiveness 074 A wide variety of new building materials have been developed and used for many common wooden houses in Japan. Among them, plywood is representative of wooden building-materials, which are used as finishing material, substrate material, structural panel and also as concrete form-board. Gypsum, an inorganic material that is used to make gypsum board, has superior fireproof and sound-insulation Plywood/New properties, excellent workability and is cost effective, which made it widely used as interior materials for ceilings Building Materials and walls. Furthermore, “wooden boards”, a generic term for OSB, particle board, MDF and the like, are also used as materials for structural substrates and furniture/woodcrafts.

Material for flat roofing that allowed for flexibility of building planar plans 075 As Japan experiences a high amount of rainfall, housing traditionally had only pitched roofs, which is effective for drainage. An asphalt roofing technique that was introduced to Japan in the Meiji era enabled construction of flat-roof buildings. Asphalt roofs were welcomed by many building designers who wanted to freely design floor plan without being restricted by the roof shape. Waterproofing for After the World War II, a new type of high-polymer material was developed, which was used for membrane Roofs waterproofing. This was widely accepted in the industry, due to its light weight and the quick installation process. For pitched roofing as well, a variety of materials were developed and diffused, such as cement-based corrugat- ed sheet, roofing slate, and metal-based materials such as zinc-coated steel sheet and galvalume steel sheet.

3 Hot-water supply system developed to respond to the needs of the times

—Equipment and Environment 076 When RC multi-unit residential buildings began to be constructed, the bathtubs installed in each housing unit had a problem with the flu gas exhaust, which was solved by the development of the BF type (closed and bal- anced flue type) bath boiler. This new equipment helped secure the safety and comfort of urban workers, who supported the sharp growth of the post-war economy in Japan. Gas Water Heaters Further efforts of seeking a more convenient, comfortable and safer lifestyle led to the development of the RF type (rooftop flue-type) water heater, which is unique to Japan. Necessitated by the oil crisis and the global trend toward environment protection that began in the late 20th century, more efficient water heaters, like Eco-Jaws and Ene-Farm, were introduced in Japan.

Equipped first in kitchens, then for toilets and in bathrooms, and finally all around the house 077 Ventilation fans became common in Japanese housing since Japan Housing Corporation (JHC) adopted them for the rental housing units, which were first constructed in the 1950s. They were provided for the purpose of preventing condensation and mold. During the 1960s, ceiling embedded ventilation fans were developed, which exhausted the air through a duct system. Ventilation Fan This ventilation system enabled to make floor plans that locate damp rooms, such as kitchens and bathrooms, in the center of the housing unit, which does not face outside. In the late 1960s and thereafter, Japanese housing became more and more airtight. To correspond to this, a continuous (24-hour) ventilation system was developed, and more recently, higher-quality ventilations systems combined with heat exchangers have appeared on the market.

A leading product for kitchen innovation that changed the image of home life 078 The lifestyle innovation that occurred in post-war Japan might be symbolized by the change to the kitchen design, with a stainless-steel sink placed in the center. Until the 1950s, most sinks were made of materials such as some metals that easily became rust stained, artificial stones or concrete. Production of stainless-steel sinks had already begun at that time, however, they were still high-end products, thus not affordable for most people. It Stainless-Steel Sinks was Japan Housing Corporation (JHC) that disseminated stainless steel sinks. Their first application was in the Harumi Danchi project that was completed in 1958, in which Hamaguchi Miho, the first female architect in Ja- pan, was deeply involved in its design. In the background of this innovation, there was an important contribution made by a company that achieved mass production of stainless-steel sinks through extrusion molding press.

077 078 080 081 source: Panasonic Ecology Systems Co., Ltd. source: Ministry of the Environment Government of Japan 100 Key Terms

26 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 3—Equipment and Environment I

Revolutionary component that solved water leaks from bathrooms 079 It is required for bathrooms to have properties of waterproofing, damp proofing, water resistance and fireproofing, except of course for the water supply and drainage systems. Traditionally in Japan, people in highly populated areas went to public bathhouses, and in the case of houses with bathtubs, bathrooms were normally located outside the house or in the corner of the house unit. Gradually, it was required to equip every housing unit Prefabricated with an individual bathroom, which led the development of prefabricated bathroom unit. This bathroom units Bathroom Unit were increasingly adopted to high-rise buildings, including hotels and multi-unit residential buildings. Because of the Japanese custom of washing themselves outside of the bathtub, prevention of water leaks was a critical II issue in constructing bathrooms. Development of the prefabricated bathroom unit was the ideal solution to the problem, and it is now indispensable for Japanese housing.

Is the Japanese-style toilet now an endangered species in Japanese housing? 080 It was about 100 years ago when the first Western style flush-water toilet was manufactured in Japan. At that time, this type of toilet was not widely accepted by people, however, it suddenly became popular since the Japan Housing Corporation (JHC: established in 1955) adopted this toilet as its standard specification. Currently, almost 100% of toilets delivered by Japanese manufacturers are Western style ones. III Western-Style Toilet It is characteristic of Japan that almost 80% of housing are currently equipped with a warm water washing toilet, called “Washlet”.

Environmental equipment that contributed to living standard improvement and aqueous environment preservation 081 IV Development of Johkasou system (domestic wastewater treatment facility) enabled to install flush toilets even in areas where sewage systems are not available, which played an important role in improving people’s lives. At Johkasou Systems first, a single-sewage treatment Johkasou was used, which treated only wastewater from commodes. This has been replaced by a multi-sewage treatment Johkasou system, which is a tank that treats sewage from com- (Domestic wastewater modes, as well as general household wastewater, including those from kitchen, washing, bathing, etc. It may be said that the role of Johkasou system changed from sanitary equipment to an environmental protection system, 074 treatment facilities) as it has greatly contributed to the preservation of the aqueous environment. The Japanese term, Johkasou, is now used overseas in reference to this unique equipment that was developed in Japan for wastewater treatment of individual households. 083

From the incandescent light and the fluorescent light to energy efficient LED V 082 In the trend of Westernization in the Meiji era in Japan called “civilization and enlightenment”, a new age of electricity began with the introduction of the incandescent lamp. Improvement of lighting appliances has been made over the years, together with advancements in creative interior designs of commercial facilities. Electrical Equipment/ In recent years, energy efficient LED has been used as a light source, replacing conventional incandescent

and fluorescent lights. 100 Lighting Appliances Electrical equipment in buildings is supported by electrical substations, which are equipped with multiple electrical lines and emergency power sources in preparation for power failures. Electric equipment of the next era will be an innovative integration of hardware, software and human ware with the aim to achieve an ideal “fusion” of building engineering and electrical engineering.

New techniques employed by learning from experiences of conflagrations 083 In the Urban Building Law formulated in 1919, installation of fire doors/windows was stipulated for parts of exterior walls that are liable to catch fire in buildings that are constructed in Fire Prevention Zones. After the Great Kanto Earthquake, it was found that the amount of damage by fire was larger than that by building collapse as a result of the quake, which accelerated the diffusion of fire doors/windows and fire shutters. Opening Protective After the Shirokiya Department Store Fire in 1932, the installation of fire shutters inside of buildings was begun Assembly in order to divide large spaces into multiple fire compartments. Following two successive fires at large commercial buildings in the 1970s, a smoke/fire preventive shutter was developed, which is highly airtight and automatically closes when smoke is sensed.

083

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 074 – 083 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

27 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS IV BUILDING PRODUCTION / FACILITIES 3—Equipment and Environment I

Technological progress of lifts to improve vertical movement of people 084 As buildings became higher, elevators, which vertically transport passengers in cages, were becoming popular. During this process, various innovative elevator-technologies have been invented. These include: an elevator with no machine room developed by minimizing the sizes of winches and control equipment; a variable double-deck elevator with an improved transportation capacity, which enables operation Elevators in buildings with floor heights that are not uniform; and an elevator that can be operated in buildings with a seismic isolation system installed in the middle floors; and an ultra-high speed elevator, exceeding 1000m/min. There are further efforts taking place now to improve the safety and security of elevators, which are: setting a II mandatory requirement for each elevator to be equipped with a device to prevent people from being trapped inside; and improving strength and durability of cables.

Born as an anti-pollution measure and now dispersed as an environmental conditioning facility 085 The district heating & cooling system is an intensive heat-source system, which mass produces cold and heat within a region and delivers cold water, hot water and steam to multiple users. The pioneering example in Japan was in the Tokyo Imperial University Hospital, where a district heating and cooling system was installed in 1895. With this system, steam was delivered to seven wards from a central boiler room, which was called “school-build- III District Heating and ing type district heating”. “Business-type district heating/cooling”, by which heat is supplied by corporations or Cooling System individuals other than the user, began in 1966 in Japan with Enzan-Kitamchi Jutaku Danchi in Sapporo city. The district heating/cooling system was incorporated in the City Planning Act in 1968 as part of the urban infrastructure, and consequently, was approved as part of the public works under the Heat Supply Business Act, 1972. Since then, it has gradually been diffused throughout Japan.

Introduced in accordance with advancements in information and communication technology IV 086 In the 1980s, an increasing number of office buildings were equipped with an abundance of electronic appliances, due to the rapidly spreading information and communication technologies, which required upgrades of the electrical, ventilation and wiring capacities of buildings, as well as consideration for the health of building occu- pants. Also, the use of computers for digitalized telecommunications together with an advanced sensor technol- Intelligent Buildings ogy brought about huge improvements in energy efficiency and optimization of building equipment as well as in the comprehensive safety of the building as a whole. Liberalization and deregulation of the telecommunication industry also had a considerable impact on the planning of buildings. In 1984, the first building to be called an “intelligent building” opened in the US, the excitement of which quickly spread to the Japanese building sector. 084

Essential elements for a sustainable society 088 087 Japanese building-insulation techniques spread from Hokkaido, the coldest region, to most other areas in Ja- pan. In 1969, a standard for building insulation was established for the purpose of reducing costs for heating, as well as preventing surface condensation on buildings. After the first oil crisis in 1973, energy conservation be- Insulation & Energy came a serious social issue, and in 1980, an enforcement order under the BSL was enacted that provided insu-

lation standards for housing together with their design and construction guidelines in order to facilitate energy 100 Efficiency savings of housing. Since then, installation of insulation has been promoted nationwide and its regulations/ standards have been amended and strengthened many times to the present day. There are various kinds of insulation materials, which are mainly grouped into two types, fiber-type and formed plastic type. In terms of insulation of windows, double-glazed windows became popular in the 21st century in Japan, which has considerably improved the insulation performance of Japanese housing.

Buildings that contribute to the creation of a sustainable society 088 At the end of the 20th century, many environmentalists started warning of global environment problems, with a prediction that if the world population and economy continued to grow, global warming and destruction of the ecology would further proceed, and thus damaged the basis of human society to the point of no return. Buildings in the modern era have been developed with a sort of ‘artificial environmental technologies’ which Sustainable Buildings allow consumption of vast amounts of energy as a necessary antecedent. New approaches for reducing ecolog- ical footprints have been explored; from the stage of production of materials, through the period of product use, to the stage of product demolition.

085 088 source: Japan Heat Supply Business Association

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 084 – 088 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

28 100 SELECTED BUILDING TECHNOLOGIES V POLICY / REGIONAL PLANNING Commentary

Disaster Prevention motion began for the construction of regional Chapter houses [095], i.e., houses that incorporated region- Japan deals with many natural disasters. It has al characteristics, which was represented by the experienced many such disasters in modern HOPE (Housing with Proper Environment) Plan. times, and the first of those to occur after the Later on, the renovation and conversion establishment of the Urban Building Law in [096] of buildings have emerged as new issues 1919, was the Great Kanto Earthquake in 1923. with the mature society and sluggish economic In Tokyo, the most seriously damaged area, the growth as a background. These are vitally im- reinforced concrete structure, a new structural portant subjects, as it is now strongly required method at that time, was used for the rebuilding to re-utilize existing buildings as social assets. of primary schools considering its superior seis- It is particularly interesting to know that mic and fire-resistive performances. These were measures taken to address these key issues later called “Fukko Shogakko (Restoration pri- have been created by grass-roots activities, rath- mary schools) [089]”. For wooden school build- er than by bureaucrats and authorities. ings built before the introduction of the rein- A type of building that is rather peculiar in forced concrete structure, improvement was this booklet, and also in Japan in general, is V also made for their structure after the Muroto colonial architecture [097]. Before the current na- typhoon hit in 1934. tional boundary was delineated, Japanese During the World War II, Japanese build- boundaries used to be extensive, and many cit-

REGIONAL PLANNING POLICY / ings that were made with wood and paper were ies and buildings were developed by the Japa- completely destroyed in great numbers by in- nese people in the areas not within present-day cendiary bombs. Reflecting this experience, Ja- Japanese territory. pan vigorously promoted the creation of cities where large conflagrations could be prevented. Legal Framework One of the measures that was proposed was the construction of fire-preventive building zones When considering how to control construction [090], which were “belts” of fireproof buildings to of buildings that constitute urban spaces, it function as firewalls for the city. These were gradually came to be realized that the existing eventually constructed in nearly 100 cities simple restriction of building height limit, which throughout the country. This idea was succeed- was provided in the Urban Building Law, was ed by the concept of fire preventive zone under not sufficient to respond to the social demands the Disaster Prevention Block Development for higher-density accommodation in urban ar- Law which was the basis of the current ur- eas and for construction of taller buildings that ban-space planning. has been enabled by advancements in technolo- Going back to the Taisho era, there had gy. Thus, the concept of floor-area-ratio restric- been many residential districts in urban areas tion [098] was thought out. that were deteriorated, thus, slum-clearance Later on, demand for building quantity was measures [091] were taken in some districts. It satisfied and the quality became an important was not until after the war, however, that exten- requirement, which included barrier-free de- sive measures were taken to address this issue, signs in special consideration for people with when it was acknowledged that the existence of disabilities and for the growing number of aged such huge areas of slums seriously impeded the people. Then its scope was extended to include development of urban areas. Among various every single person, not only people in need, countermeasures, one notable project was which is known as universal design [099]. “Sakaide Artificial Ground”, developed in 1968, It is said that generally, formation/revision which was an attempt to create a comfortable of legislation tends to follow social movements. residential environment in collaboration with a Under such a tendency, the most important challenging type of architecture. change of the Japanese building legislation in Under the economic prosperity afterwards, the 20th century must have been the introduc- concentrations of people in urban areas became tion of performance-based building regula- conspicuous, and cities were fully built-up with tions/standards [100] from the conventional spec- housing. When the Great Hanshin-Awaji Earth- ification-based standards. This revision was quake occurred, in 1995, this congestive-city made with the aim to ensure that building stan- problem was suddenly recognized as a serious dards may swiftly reflect technical develop- social issue. Through this experience, measures ments of the time. The revision has had some for densely populated urban areas [092] were es- positive effects so far and is expected to gener- tablished to address the problems related to ate more significant results in the future. over-developed cities, and to improve living environments by, for example, providing a sufficient number of open spaces in urban areas.

Culture

In the process of social restoration, problems arising in line with the economic growth were demolition of historically significant buildings, together with the surrounding traditional streetscapes. Various policy measures have been proposed to address this issue which, however, do not seem to be sufficient. Concepts ofpreserva - tion/conservation of historic architecture [093] and conservation of townscape [094] still remain as challenging issues. On the other hand, when a massive housing supply was urgently required, houses were built in a stereotyped style; all of the same design and with the same materials. When the housing shortage problem was resolved, pro-

29 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS V POLICY / REGIONAL PLANNING 1—Disaster Prevention / 2—Culture

1 A new type of school building, born of the rebuilding after the Great Kanto Earthquake

—Disaster Prevention 089 Fukko Shogakko (Restoration primary schools) are a group of primary schools that were constructed during the course of rebuilding around Japan after the Great Kanto Earthquake. By applying a design code specifically developed for the schools, these reinforced-concrete school buildings enabled sufficient fireproof and seismic performances in a short period of time. Fukko Shogakko Some of the objectives of Fukko Shogakko were implementing the New Education proposed in the Taisho era in (Restoration primary Japan and serving as cores of the social education of each region. To this end, these schools were planned to schools) have multiple functions, which later formed a basic concept of the current “open schools”.

Building shields to prevent fires in urban areas 090 There are several ways to make a city fireproof; however, in existing urban areas, it is difficult to implement such measures as they would require drastic renovation of the structures of cities. To solve this difficulty, an innovative plan was thought out from the viewpoint of “turning a war disaster into an advantage”, which was development of fire preventive building zones; belts of nonflammable buildings that could prevent the spread of fire, Fire Preventive much like shields to protect the city. Fire preventive building zones were usually constructed along main streets. Building Zones In some cities, these zones gradually formed shopping streets with stores like row-house, which attracted people to move there, and they eventually became lively city-centers. Fire preventive building zones contributed not simply to creating fireproof cities, but also to keeping the quality of people’s living and to forming the townscape as well.

Improve deteriorated residential areas to create new living environment 091 It was 1920 in Japan when measures were taken to address the problem of slums as there was a sudden increase of deteriorated residential areas, which was caused by the rapid urbanization and industrialization of large cities. In accordance with the Act for the Improvement of Deteriorated Residential Areas formulated in 1927, scrap-and-build style residential redevelopments were implemented, that was; within a district designated Slum Clearance for residential improvement, demolished old houses and constructed a sufficient number of new houses so that the existing residents could continue to live in that district. In the economic growth period after the war, deteriorated residential areas were considered to be a hindrance to the development of the city as a whole. Succeed- ing the previous act, the Act for the Improvement of Residential Areas was formulated in 1960. Based on this new act, the Sakaide Artificial Ground in Kagawa prefecture and Motomachi/Chojuen housing complexes in Hiroshima city were constructed.

From improvement of the living environment to strengthening disaster prevention 092 Densely populated urban areas have long been a serious problem in the history of city planning in Japan, and many measures were taken to cope with this issue, including slum clearance. When the World War II ended, new housing supply programs were carried out in the Kyojima district in Tokyo and some other areas, by which new public housing was provided for existing residents of the area, while re- Measures for building the deteriorated houses. Densely Populated After the Hanshin-Awaji Great Earthquake, the function of disaster prevention was considered to be more important than the improvement of the residential environment in densely populated urban areas. Urban Areas Current measures taken to address the issue include; providing more area for public open-spaces, increasing floor area in fire-resistive buildings, and providing streets that could function as firebreaks.

2 Formulating legislation for utilizing stock in urban areas

—Culture 093 In the period of high economic growth, it was difficult to preserve/conserve historic architecture, as the efficient use of land had a top priority. In recent years, however, it has become important to efficiently utilize stock (existing architectural resources), while carrying out urban renewal projects. Accordingly, various legislation has been formulated to allow for de- Preservation/ velopment, and at the same time, the preservation/conservation of existing resources as well. Conservation of While the need for preservation/conservation of valuable buildings is growing, new approaches have recently been taken, such as commissioning local governments to legislate their own regulations to preserve/conserve Historic Architecture historic resources in their jurisdictions.

090 092 093 094 100 Key Terms

30 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS V POLICY / REGIONAL PLANNING 3—Legal Framework I

“Favorable townscape”, identified by each region 094 Measures for townscape conservation have been implemented under joint enforcement of the Law for the Pro- tection of Cultural Properties, the City Planning Act and the Building Standard Law. From the 1960s to the 1970s, a movement to conserve townscapes occurred across the country, which led to the current activities of re-evaluating and maintaining old and modern architecture that form townscapes unique Conservation of to each region, although they are not as valuable as national cultural resources. Townscapes Various measures are now being developed to create beautiful townscapes for the future, which will remain as one of the scenes of the history, while respecting the characteristics of each region. II

Measures to provide houses suited to each local climate and culture 095 Beginning in the Meiji era, Japan adopted Western style housing with both the exterior look and designs of the living space. After the World War II, there was no room to consider the regional climate or culture when constructing houses, due to a severe shortage of building materials and labor for the huge housing demand. Under the sharp economic growth afterwards, a nationwide housing provision plan was carried out, facilitated by the Regional Houses development of new building materials/components and production technologies, as well as the trends towards III the nuclear family and urbanization. However, houses had traditionally been built with floor plans, forms and materials that reflected each regional characteristic. Those houses actually created the townscape and scenic beauty that is unique to the region, which eventually generated a specific local attractiveness. Based on such view, the “HOPE (Housing with Proper Environment) Plan” started in 1983 as a government program for promoting housing that is suitable for each regional climate and culture. IV Towards new value of architecture created by growing imagination for building usage 096 From the late 1990s through the first decade of the 2000s, there was a fundamental shift in the Japanese building industry; from the period when newly built construction was dominant, to the era of repair/renovation/usage conversion of existing buildings. Housing starts, which once reached almost two million units a year, steadily declined and have been fewer than Renovation/ one million units a year since 2009. Currently, the housing stock surplus is a serious problem that reflects the Conversion shrinking population. In order to utilize the value of the housing stock, renovation/conversion is inevitable to keep them as social assets. This idea is now a major trend in the building industry and in the cultural sector as well.

Facilities/style/structure/regulations that demonstrates governing power 089 Japan constructed a variety of buildings in colonies that Japan governed from the end of the 19th century 097 th through the early 20 century. The priorities were facilities required for colonial governance, which were government buildings and hospitals.

Colonial Architecture Brick construction was used for the structures of these buildings for the purpose of making the cities safe from 098

fires, while maintaining their aesthetic value. 100 Initially, those buildings were modeled after the architecture of powerful Western countries, such as Queen Anne style- and Neo-Baroque style buildings. However, in 1931, when the Manchurian incident occurred, Japan began to adopt Asian-style architectural designs.

3 A means to regulate density in urban areas

—Legal Framework 098 As the total floor area of buildings grows, the active population of the area increases, which imposes a bigger load on the infrastructure, such as roads and water/sewage systems. The restriction of the floor-area ratio is a measure to balance the total building floor area of a city and the capacity of the city’s infrastructure by restricting the ratio of the total floor area of each building to the building lot. Restriction of Floor In the old days, the density of a city was controlled indirectly by restrictions on the maximum building height Area Ratio and the building coverage ratio. To comply with the boom of higher and larger-scale building construction during the period of high economic growth, the density control method was changed in favor of the restriction of floor-area ratio.

096 097 photo: NISHIZAWA Yasuhiko

the Edo era: 1603–1868 / the Meiji era: 1868–1912 / the Taisho era: 1912–1926 / 089 – 098 the Showa era: 1926–1989 / the Heisei era: 1989–2019 / the Reiwa era: 2019–

31 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS V POLICY / REGIONAL PLANNING 3—Legal Framework I

From barrier-free for the disabled, to a subject common to all human beings 099 The barrier-free design, which was established during the 1980s in Japan, was based on the premise of exclud- ing all existing barriers in the physical environment, people’s consciousness, information and social systems. Beginning in the 21st century, on the other hand, a universal design spread, which aims to allow access to as many people as possible to spaces, the environment, products, and the provision of services. Universal Design A point common to both barrier-free and universal design is their objectives, which is to establish cities and a society where diversity is accepted and no discrimination exists, in order to eliminate existing barriers and to prevent the creation of new barriers in the future. II

Changed to legislation that enhances design flexibility and introduction of new technologies 100 Specification-based regulations/standards require buildings to conform to specifications of size, shape, used materials, etc. that are stipulated in the regulations, whereas performance-based regulations/standards simply require buildings to have a certain level of performance. Under performance-based regulations/standards, it is possible to use various materials, equipment and structural methods if they satisfy the required performance, Introduction of which heighten the flexibility of building designs, and also streamline the process of introducing new technolo- III Performance-Based gies and products from overseas. The Building Standard Law was initially established as specification-based regulations/standards. For products/technologies not specified in the Law, it was required to obtain approvals Building Regulations/ under Article 38 of the Law. In 2000, the Building Standard Law was drastically revised in order to incorporate Standards performance-based regulations/standards into it.

099 – 100 IV

100th Anniversary of Enactment of City Planning Act and Building Standard Law

Architecture that Supported Modernization of Japan V – 100 selected building technologies 099 100

Table of Contents

- Preface - Contents - Chronology - Overview: Modern and Contemporary Japan Supported by Architecture - 100 Selected Building Technologies Chapter 1 Housing Chapter 2 Buildings Chapter 3 Structural Methods Chapter 4 Building Production/Facilities Chapter 5 Policy/Regional Planning - Roundtable Talk: - Index - Writers Profiles

Published in: June 2019 Phone: +81-3-5283-0461 Edited by: Committee for: URL: https://www.bcj.or.jp/ “Architecture that Supported Modernization of Japan” Price: Japanese yen 4,500- Published by: The Building Center of Japan The Japan Architectural Education and Information Center ISBN 978-4-88910-177-5 Contact: The Building Center of Japan (This number is for the book in Japanese language) 1-9, Kanda-Nishikicho, Chiyoda-ku, Tokyo, 101-8986, JAPAN ©2019, The Building Center of Japan

32 100 SELECTED BUILDING TECHNOLOGIES 100 KEY TERMS Writers

Writers of “Key Terms of 100 Selected Building Technologies”

001 Residential Suburbs OBASE Reiji 051 Tubular Structures TAKEUCHI Toru 002 Dojun-kai Apartments OTSUKI Toshio 052 Shell/Spatial Structures SAITOH Masao 003 Coal Miners’ Housing KIKUCHI Shigetomo 053 Membrane Structures KAWAGUCHI Ken’ ichi 004 Publicly-Operated Housing and Japan Housing Corporation (JHC) 054 Retractable-Roof Domes KAWAGUCHI Ken’ ichi Housing TAKADA Mitsuo 055 Seismic Technology for Wooden Housing SAKAMOTO Isao 005 Danchi UEDA Makoto 056 Structural Analysis of Traditional Wooden Buildings 006 New Towns NARUMI Kunihiro KAWAI Naohito 007 Condominiums KOBAYASHI Hideki 057 Two-by-Four Buildings ABE Ichiroh 008 Multi-Unit Housing Operated by Private Sector MORIMOTO Nobuaki 058 Fire Preventive Construction HASEMI Yuji 009 Cooperative House (Building co-operatives) NAKABAYASHI Yoshiyuki 059 Fire-Resistive Wooden Buildings YASUI Noboru 010 Collective Housing HINOKIDANI Mieko 060 Large-Scale Timber Buildings KOSHIHARA Mikio 011 Skyscraper Condominiums ANDO Masao 061 Cast-in-Place Concrete NOGUCHI Takafumi 012 Emergency Temporary Housing and Restoration Housing 062 Alternative Materials e.g. Bamboo-Reinforced Concrete WATANABE Shiro HAYAMI Kiyotaka 013 Minimal Houses TSUKAMOTO Yoshiharu 063 Exposed Concrete Finish FUJIMORI Terunobu 014 GHLC Specification MIZUTANI Tatsuro 064 PCa Concrete/PC OKAMOTO Shin 015 Cold-Region Housing TANIGUCHI Naohiro 065 Foundation/Ground Improvement FUJII Mamoru 016 Housing for the Elderly SONODA Mariko 066 Reuse/Recycling of Building Materials TSUNODA Makoto 017 Housing Performance Indication System SUMIKURA Hideaki 067 Measures to Ensure Safety of Workers KANISAWA Hirotake 018 Prefabricated Housing MATSUMURA Shuichi 068 CAD/BIM KANO Naruo 019 Pilot Projects YOSHIDA Takuro 069 Exterior Tiles OMI Yasuo 020 Skelton-Infill House (Base building and fit-out for housing) 070 Aluminum Sashes MANABE Tsunehiro MINAMI Kazunobu 071 Curtain Walls SEIKE Tsuyoshi 021 Precutting GONDO Tomoyuki 072 Glass Buildings INOUE Tomo 022 School Buildings NAGASAWA Satoru 073 ALC KITSUTAKA Yoshinori 023 Public Cultural Facilities SATOH Shinya 074 Plywood/New Building Materials ANDO Naoto 024 Government Buildings ISHIDA Junichiro 075 Waterproofing for Roofs TANAKA Kyoji 025 Modern Architecture YAMANA Yoshiyuki 076 Gas Water Heaters KURABUCHI Takashi 026 Okinawan Architecture MATSUBA Kazukiyo 077 Ventilation Fan KOMINE Hiromi 027 Religious Buildings and Memorials IGARASHI Taro 078 Stainless Steel Sinks WADA Nahoko 028 Tower YOSHIMI Shunya 079 Prefabricated Bathroom Unit MANABE Tsunehiro 029 The Tokyo Olympics TOYOKAWA Saikaku 080 Western-Style Toilet KAMATA Motoyasu 030 Japan World Exposition, Osaka 1970 HASHIZUME Shinya 081 Johkasou Systems (Domestic wastewater treatment facilities) 031 Station Buildings with Shoppping Centers FUJIMURA Ryuji IWAHORI Keisuke 032 Arcade TSUJIHARA Makihiko 082 Electrical Equipment/Lighting Appliances GOTO Masahiro 033 Underground Mall HATSUDA Kosei 083 Opening Protective Assembly HAGIWARA Ichiro 034 Pedestrian Decks FUJIMURA Ryuji 084 Elevators FUJITA Satoshi 035 Public Open Spaces ASAMI Yasushi 085 District Heating and Cooling System IBAMOTO Tadahiko 036 Urban Redevelopment ASAMI Yasushi 086 Intelligent Buildings OKISHIO Soichiro 037 Urban Waterfront Development YOKOUCHI Norihisa 087 Insulation & Energy Efficiency SAKAMOTO Yuzo 038 Shopping Mall MATSUBA Kazukiyo 088 Sustainable Buildings KODAMA Yuichiro 039 Downtown ISHIGURE Masakazu 089 Fukko Shogakko (Restoration primary schools) KANAYAMA Mahito 040 Convention Center ISO Tatsuo 090 Fire Preventive Building Zones HAYAMI Kiyotaka 041 Theme Parks INOUE Shouichi 091 Slum Clearance ISHIGURE Masakazu 042 Concrete Block Structures KUMAGAI Ryohei 092 Measures for Densely Populated Urban Areas YAMAMOTO Toshiya 043 Steel Structures YAMADA Satoshi 093 Preservation/Conservation of Historic Architecture 044 Steel Encased Reinforced Concrete Structures KUMAGAI Ryohei GOTO Osamu 045 Reinforced Concrete Structures FUJIOKA Hiroyasu 094 Conservation of Townscapes EBARA Sumiko 046 Seismic Design Provisions SHIOHARA Hitoshi 095 Regional Houses MIISHO Kiyonori 047 Seismic Isolation Systems NISHIKAWA Takao 096 Renovation/Conversion SYNBORI Manabu 048 Response Control WADA Akira 097 Colonial Architecture NISHIZAWA Yasuhiko 049 Seismic Retrofit NAKANO Yoshiaki 098 Restriction of Floor Area Ratio OSAWA Akihiko 050 Skyscrapers GONDO Tomoyuki 099 Universal Design TAKAHASHI Gihei 100 Introduction of Performance-Based Building Regulations/Standards GOJO Wataru

C3 100 SELECTED BUILDING TECHNOLOGIES Architecture That Supported Modernization of Japan 002 003 005 007 100 selected building technologies An English Summary

022 024 025 026

034 036 037 040

042 044 045 049

061 062 064 066

090 092 093 094

MORI Masayo International Consultant and Translator Area of expertise: Buildings and wood products

ISO Tatsuo Editor

ARATAME Shinobu Book Design